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Bulletin  292  December,  1927  (\  0  /^  /^j 

Qlnnttfrttrut  Ajrtntltural  lEscperimMtt  3*1310111 

43 

Some  Insect  Pests  of  Nursery  Stock 
in  Connecticut 


W.  E.  BRITTON  and  M.  P.  ZAPPE 


The  Bulletins  of  this   Station  are  mailed  free  to  citizens  of  Connecticut 
who  apply  for  them,  and  to  other  applicants  as  far  as  the  editions  permit. 


on 


CONNECTICUT  AGRICULTURAL  EXPERIMENT  STATION 

OFFICERS   AND    STAFF 


BOARD  OF  CONTROL 

His  Excellency,  John  H.  Trumbull,  ex-officio.  President 

Charles  R.  Treat,  Vice-President Orange 

George  A.  Hopson,  Secretary Mount  Carmel 

Wm.  L.  Slate,  Director  and  Treasurer New  Haven 

Joseph  W.  Alsop Avon 

Elijah   Rogers Southington 

Edward  C.  Schneider Middletown 

Francis   F.   Lincoln Cheshire 


Administration. 


Chemistry. 
Analytical 
Laboratory. 


Biochemical 
Laboratory. 


Botany. 


Forestry. 

Plant  Breeding. 
Soil  Research. 


Tobacco  Sub-station 
at  Windsor. 


STAFF. 

E.  H.   Jenkins,   Ph.D.,  Director  Emeritus. 

Wm.  L.  Slate,  B.Sc,  Director  and  Treasurer. 

Miss  L.  M.  Brautlecht,  Bookkeeper  and  Librarian. 

Miss  J.   V.  Bekger,  Assistant  Bookkeeper. 

Mrs.  R.  a.  Hunter,  Secretary. 

G.  E.  Graham,  In  charge  of  Buildings  and  Grounds. 

E.  M.  Bailey.   Ph.D.,  Chemist  in  Charge. 

C.    E.    Shepard 

Owen  L.  Nolan 

Harry  J.  Fisher,  A.B.       [    Assistant  Chemists. 

David  C.  Walden,  B.S. 

W.   T.  Mathis  J 

Frank  C.   Sheldon,   Laboratory  Assistant. 

V.  L.  Churchill,  Sampling  Agent. 

Miss  Mabel  Bacon,  Secretary. 

T.   B.  Osborne,   Ph.D.,  Chemist  in  Charge. 

H.   B.  Vickery,  Ph.D.,  Biochemist.  * 

Miss  Helen  C.  Cannon,  B.S.,  Dietitian. 

G.   P.   Clinton,   ScD.,   Botanist  in  Charge. 

E.  M.  Stoddard,  B.S.,  Pomologist. 

Miss  Florence  A.  McCormick,   Ph.D.,  Pathologist. 

George  L.   Zundel,  M.S. A.,   Graduate  Assistant. 

A.  D.  McDonnell,  General  Assistant. 

Mrs.  W.   M.   Kelsey,  Secretary. 


W. 


E.    Britton,    Ph.D.,    Entomologist   in    Charge;    State 
Entomologist. 


B.  H.  Walden,   B.Ace. 
M.  p.  Zappe,  B.S. 
Philip  Garman,  Ph.D 
Roger  B.  Friend,  Ph.D 
J 


Assistant  Entomologists. 


P.   Johnson,   B.S.,   Deputy  in  Charge  of  Japanese  Beetle 
Quarantine. 
John  T.  Ash  worth.  Deputy  in  Charge  of  Gipsy  Moth  Work. 
R.  C.  Botsford,  Deputy  in  Charge  of  Mosquito  Elimination. 
Miss  Grace  A.  Foote,  B.A.,  Secretary. 

Walter  O.   Filley,  Forester  in  Charge. 

H.  W.  Hicock,  M.F.,  Assistant  Forester. 

J.  E.  Riley,  Jr.,  M.F.,  In  Charge  of  Blister  Rust  Control. 

H.  J.  LUTZ,  M.F.,  Assistant  Forester. 

Miss  Pauline  A.  Merchant,  Secretary. 

Donald  F.  Jones,  S.D.,  Geneticist  in  Charge. 
W.  R.  Singleton,  S.M.,   Assistant  Geneticist. 
H.  R.  Murray,   B.S.,   Graduate  Assistant. 

^M.  F.  Morgan,  M.S.,  Agronomist. 
H.  G.  M.   Jacobson,  M.S.,  Assistant. 
Miss  Evelyn  M.  Gray,  Secretary. 

Paul  J.  Anderson,  Ph.D.,  Pathologist  in  Charge. 
N.  T.  Nelson,  Ph.D.,  Assistant  Physiologist. 
T.   R.   Swanback,   B.S.,   Scientific  Assistant. 


QUINNIPIACK  PRESS,  INC.,  NEW  HAVEN 


CONTENTS 


PAGE 

General  Feeders 119 

Leopard  Moth 120 

Fall  Webworm 120 

Cankerworms 120 

Tussock  Moths 121 

Gipsy  Moth 122 

European  Fruit  Lecanium 123 

Oyster-shell  Scale 123 

Insects  Injuring  Fruit  Stock 124 

Eastern  Tent  Caterpillar 125 

Apple  and  Thorn  Skeletonizer 126 

Red-humped  Caterpillar 126 

Yellow-necked  Caterpillar 127 

Japanese  Beetle 127 

Rose  Chafer 128 

Pear  Slug 129 

Imported  Currant  Worm 129 

Climbing  Cutworms 130 

New  York  Weevil 131 

Apple  Tree  Borers 131 

Oriental  Peach  Moth 132 

Peach  Borer 132 

Shot-hole  Borer 133 

Imported  Currant  Borer 134 

Green  Apple  Aphid 134 

Woolly  Apple  Aphid 135 

Black  Cherry  Aphid 136 

Currant  Aphids 136 

San  Jose  Scale 137 

Scurfy  Scale 137 

Leaf  Hoppers  on  Apple 138 

Tarnished  Plant  Bug 139 

Pear  Leaf  Blister  Mite 140 

European  Red  Mite 140 

Insects  Injuring  Deciduous  Shade  and  Forest  Trees 141 

Larch  Case  Bearer 142 

Locust  Leaf  Miner 143 

Imported  Birch  Leaf  Miner 143 

Birch  Skeletonizer 144 

Elm  Leaf  Beetle 144 

Willow  Flea  Beetle 145 

Imported  Willow  Leaf  Beetle 145 

Cottonwood  Leaf  Beetle 145 


Spotted  Willow  Leaf  Beetle 145 

Poplar  Tent  Maker 146 

Larch  Sawfly 146 

Bronze  Birch  Borer 147 

Linden  Borer 148 

Locust  Borer 148 

Poplar  and  Willow  Borer 149 

Mites 150 

Green  Aphids 150 

Beech  Woolly  Aphid 151 

Willow  Aphids 151 

Oak  Gall  Scale 151 

Pit-making  Oak  Scale 151 

Tulip  Tree  Scale 152 

Terrapin  Scale 152 

European  Elm  Scale 153 

Cottony  Maple  Scale 153 

Elm  Scurfy  Scale 154 

Insects  Injuring  Shrubs  and  Vines 154 

lo  Caterpillar 155 

Saddle-back  Caterpillar 155 

Sphinx  Caterpillars  or  Horn  Worms 156 

Pipe-vine  Caterpillar 156 

Cecropia  Caterpillar 156 

Eight-spotted  Forester 157 

Rose  Sawfiies 157 

Honeysuckle  Sawflies 158 

Lilac  Borer 158 

Rose  Stem  Girdier 158 

Grape-vine  Tomato  Gall 158 

Eriophyid  Mites 159 

Euonymus  Scale 159 

Rose  Scale 159 

White  Peach  Scale 159 

Insect  Pests  of  Evergreen  Trees  and  Shrubs 160 

Pine  Sawflies. 161 

Juniper  Webworm 161 

Arborvitae  Leaf-Miner 161 

Boxwood  Leaf-Miner 162 

European  Pine  Shoot  Moth 162 

Spruce  Budworm 162 

Pales  Weevil 163 

Otiorhynchid  Weevils 163 

White  Grubs 164 

White  Pine  Weevil 164 

Rhododendron  Borer 165 

Spruce  Gall  Aphids 165 

Pine  Bark  Aphid 166 

Pine  Leaf  Scale 166 


Juniper  Scale 167 

Rhododendron  Lace  Bug 167 

Spruce  Mite 167 

Insects  Injuring  Perennial  Plants 168 

Columbine  Leaf-Miner 168 

Garden  Spring-Tail 169 

Cutworms 169 

Garden  Slugs 170 

Stalk  Borer 170 

Iris  Root  Borer 171 

Cyclamen  Mite 172 

Four-lined  Plant-Bug 172 


Some  Insect  Pests  of  Nursery  Stock 
in  Connecticut 

W.  E.  Britton  and  M.  P.  Zappe 


Just  about  thirty  years  ago,  the  first  nursery  inspections  were 
made  in  Connecticut  at  the  request  of  nurserymen,  so  that  they 
could  advertise  their  stock  as  having  been  officially  inspected.  In 
1901,  the  General  Assembly  passed  a  law  establishing  the  office  of 
State  Entomologist  and  providing  for  the  annual  inspection  of 
nurseries.  Thus  for  twenty-seven  years  all  nurseries  have  been 
inspected  each  year  as  required  by  law,  and  records  are  available 
showing  the  various  insects  found  on  the  many  species  and  va- 
rieties of  fruit,  shade,  forest,  and  ornamental  stock.  The  more 
important  insect  pests  are  treated  in  this  bulletin  for  the  guidance 
of  nurserymen  and  plant  growers  throughout  the  State. 

For  convenience  in  identifying  nursery  insects,  brief  keys  are 
arranged  under  each  of  the  following  classes :  General  Feeders ; 
Insects  Injuring  Fruit  Stock;  Shade  and  Forest  Trees;  Shrubs 
and  Vines  ;  Evergreens  ;  Perennials. 

Following  the  account  of  each  insect  in  most  cases,  one  or  two 
references  are  given  where  more  complete  information  may  be 
found,  mostly  reports  and  bulletins  of  this  Station  and  of  the 
United  States  Department  of  Agriculture. 


GENERAL  FEEDERS 
Key 

Chewing  caterpillars  devouring  the  tissues  2 

Scale  insects  on  bark,  sucking  the  sap  6 

Feeding  upon  the  leaves   3 

Boring  in  the  wood  Leopard  Moth,  p.  120 

Making  no  conspicuous  nest  or  web  4 

Hairy  caterpillars  feeding  in  web  at  end  of  branches, 

Fall  Webworm,  p.  120 

Caterpillars  covered  with  prominent  hairs   5 

Caterpillars  smooth,  making  loop  when  crawling,  Cankerworms,  p.  120 

With  black,  white,  or  yellow  tufts  of  hair Tussock  Moths,  p.  121 

Gray  or  brown,  without  black,  white,  or  yellow  tufts ;  first  five  pairs 

of  tubercles  blue,  remaining  six  pairs  red Gipsy  Moth,  p.   122 

Convex  hemispherical  brown  shells. .  .European  Fruit  Lecanium,  p.  123 
Elongated  curved  shells,  nearly  the  same  color  as  bark, 

Oyster-shell  Scale,  p.  123 


I20  CONNECTICUT   EXPERIMENT  STATION  BULLETIN   292 

Leopard  Moth  {Zeuzera  pyrina  Linn.) 

The  larva  of  the  leopard  moth  is  a  borer  in  the  wood  of  nearly- 
all  kinds  of  deciduous  trees  and  frequently  is  found  in  nursery 
stock — especially  in  apple  trees.  It  requires  two  years  for  its  com- 
plete development.  The  adults  emerge  and  the  female  lays  eggs 
on  the  bark  in  July.  The  young  larva  tunnels  in  small  twigs,  which 
often  break  off,  and  then  the  borer  enters  the  trunk  or  larger 
branches.  It  pupates  in  the  burrow,  from  which  the  adult  emerg- 
es, leaving  the  pupa  case  protruding  from  the  tree.  The  mature 
larva  is  about  two  inches  long  and  is  whitish,  with  tubercles,  head, 
cervical  and  anal  shields  dark  brown  or  black,  and  is  shown  on 
Plate  I,  d.  The  adults  are  a  dirty  white  with  semi-transparent 
wings  marked  with  metallic  blue  dots  and  have  a  wing  expanse 
of  about  one  and  three-fourths  inches  in  the  male  to  two  and  one- 
half  inches  in  the  female.  In  small  nursery  trees  it  is  best  to  de- 
stroy the  tree  or  branch  infested.  In  larger  trees  it  is  possible  to 
kill  the  borers  with  knife  or  wire,  or  inject  a  few  drops  of  carbon 
disulphide  and  close  the  mouth  of  the  tunnel. 

(Bulletin  169). 

Fall  Web  worm   (Hyphantria  cunea  Drury) 

All  kinds  of  fruit,  shade,  and  forest  deciduous  trees  and  shrubs 
are  subject  to  the  attack  of  the  fall  webworm.  This  insect  makes 
webs  or  nests  on  the  ends  of  branches  late  in  summer,  and  the 
caterpillars  feed  inside  them.  The  nests  are  most  noticeable  in 
August  and  September,  though  an  occasional  nest  may  be  seen 
in  June,  and  a  larger  number  in  July.  Nests  are  shown  on  Plate 
II,  a.  There  is  one  generation  each  year,  with  a  partial  second  in 
Connecticut.  The  earliest  nests  may  produce  webworms  which 
develop  to  the  adult  stage  the  same  season,  and  the  females  lay 
eggs  for  the  second  generation.  The  adult  is  a  white  moth  which 
lays  eggs  in  a  compact  mass  on  the  under  side  of  a  leaf.  The 
young  caterpillars  make  a  nest  enclosing  the  leaves  on  the  end  of 
a  branch.  After  devouring  the  food,  they  extend  the  nest  to  in- 
clude more  leaves.  The  mature  caterpillars  are  more  than  an 
inch  long,  striped  lengthwise  with  brown  and  yellow,  and  covered 
with  brownish  hairs. 

Trees  may  be  protected  by  spraying  with  lead  arsenate,  and  the 
nests  may  be  destroyed  by  clipping  off  and  burning  them. 

(Report  for  1917,  page  319). 

Cankervvorms 

Cankerworms  are  small  looping  caterpillars  which  feed  upon  the 
leaves  during  May.  Some  are  green  and  others  are  dark  brown  or 
gray.    Two  species  are  involved.    The  more  common  one  in  Con- 


INSECT  PESTS  OF  NURSERY  STOCK 


121 


necticut  is  known  as  the  fall  cankerworm,  Alsophila  pomctaria 
Harris,  because  the  moths  emerge  and  the  females  lay  their  eggs 
in  late  fall.  These  eggs  are  gray,  cylindrical,  and  laid  on  the  bark 
in  compact  clusters  of  about  one  hundred  eggs  arranged  side  by 
side  and  all  standing  on  end.  (Shown  in  Fig.  ii  and  on  Plate  I, 
a,  b,  c).  The  other  species  is  called  the  spring  cankerworm,  Palea- 
crita  vernata  Peck,  and  lays  its  eggs  in  loose  clusters  on  the  bark 
in  March.  These  egg-clusters  contain  an  average  of  about  fifty 
eggs  each  and  are  not  all  arranged  on  end  like  those  of  the  fall 
cankerworm. 

The  caterpillars  of  both  species  appear  at  the  same  time  and 
cause  the  same  type  of  injury  to  the  leaves.     They  niay  be  distin- 


FiG.  II.    Cankerworms. 


Fig.   12.     Larva  of  the  white- 
marked  tussock  moth. 


guished  by  the  fact  that  the  fall  cankerworm  has  a  pair  of  pro-legs 
on  the  eighth  segment,  which  are  absent  in  the  spring  canker- 
worm. 

Each  has  a  single  generation  annually.  The  caterpillars  usually 
become  full  grown  by  the  first  week  of  June  and  enter  the  ground 
to  pupate.  The  females  of  both  species  are  without  wings  and 
are  obliged  to  crawl  up  the  trunks  of  trees  in  order  to  lay  their 
eggs.    The  males  have  wings  and  are  ash-gray  in  color. 

Spraying  the  foliage  with  lead  arsenate  is  the  remedy. 

(Bulletin  1238,  U.  S.  Dept.  of  Agriculture). 


Tussock  Moths 

There  are  several  species  of  tussock  moths,  the  larvae  of  which 
devour  the  leaves  of  deciduous  trees  and  shrubs.  Perhaps  the 
most  irnportant  is  the  white-marked  tussock  moth,  H~enierocampa 
leucosfigma  S.  &  A.,  which  has  two  generations  each  season.  It 
hibernates  in  the  egg  stage  as  glistening  white  frothy  egg-clusters 
on  the  bark  of  trees.  The  caterpillars  present  a  very  striking  ap- 
pearance, being  striped  lengthwise  with  brown  and  yellow;  the 
head  is  bright  red  and  there  are  four  tufts  of  white  or  buflf  up- 


122  CONNECTICUT  EXPERIMENT  STATION  BULLETIN  292 

Standing  hairs  on  the  back ;  two  forward-reaching  pencils  of  long 
black  hairs  are  borne  near  the  head  and  a  similar  one  reaches 
backward  near  the  tail,  as  shown  in  Fig.  12  and  on  Plate  II,  c. 

The  caterpillars  feed  on  the  leaves  of  fruit  trees,  and  shade  and 
forest  trees,  especially  elm,  maple,  linden,  and  horsechestnut.  The 
female  is  wingless  and  lays  its  eggs  on  the  old  cocoon,  as  shown 
on  Plate  II,  f. 

The  hickory  tussock  moth,  Halisidota  caryae  Harris,  has  one 
generation  annually,  and  the  caterpillar,  shown  on  Plate  II,  b,  is 
covered  with  white  hairs  marked  with  black  hairs  to  form  a  black 
median  line,  and  two  pencils  of  black  hairs  at  each  end  of  the 
body.  It  feeds  upon  hickory,  apple,  oak,  elm,  maple,  poplar,  lin- 
den, and  many  other  trees.  The  tessellated  tussock  moth,  H.  tes- 
sellaris  S.  &  A.,  also  feeds  upon  a  large  number  of  shade  and  forest 
trees,  though  it  is  usually  less  abundant  than  the  hickory  or  white- 
marked  tussock  moths.  .  Its  caterpillar  resembles  caryae  but  has 
light  brown  instead  of  white  hairs. 

The  remedy  for  all  three  species  is  to  spray  the  foliage  with 
lead  arsenate. 

(Report  for  1917,  page  325). 


Gipsy  Moth  {Porthetria  dispar  Linn.) 

Though  not  particularly  a  pest  of  nursery  stock,  in  seriously 
infested  areas  it  may  be  considered  as  such.  There  is  but  one 
generation  each  year,  the  eggs  being  laid  in  midsummer  and  hatch- 
ing the  following  spring.  The  caterpillars  feed  from  birth,  about 
May  I,  until  fully  grown,  late  in  June.  They  are  about  two  inches 
in  length,  hairy,  and  generally  of  a  brownish  or  grayish  color, 
sometimes  with  a  distinct  median  stripe,  each  side  of  which  there 
is  a  row  of  tubercles  or  spots.  Beginning  with  the  head,  the  first 
five  pairs  of  tubercles  are  bright  blue,  and  the  remaining  six  pairs 
are  a  dull  brick  red. 

The  pupae  are  formed  in  cavities,  crotches,  on  the  under  side  of 
branches,  fence  rails,  and  in  other  protected  situations.  From  ten 
to  fourteen  days  are  passed  in  this  stage,  when  the  adults  emerge. 
The  male  is  usually  a  light,  grayish-brown  moth  with  a  wing- 
spread  of  about  one  and  one-half  inches,  though  varying  to  dark 
brown.  It  is  a  strong  flyer  and  flies  during  the  day.  The  female 
has  a  heavy  body  and  does  not  fly,  is  dirty  white  or  buff  in  color, 
with  wings  marked  with  brownish  zigzag  cross-bands,  as  shown  in 
Fig.  13.  It  has  a  wing  expanse  of  two  inches  or  more  and  is  usu- 
ally seen  resting  on  the  trunks  or  branches  of  trees  where  the  eggs 
are  laid.  The  eggs  are  laid  in  clusters  of  200  to  400  each  and  are 
covered  with  hairs  from  the  body  pf  the  female  parent.  These 
clusters  are  about  an  inch  long  and  two-thirds  as  broad.     They 


INSECT  PESTS  OF  NURSERY  STOCK 


123 


look  and  feel  like  a  bit  of  chamois  skin.  An  egg  cluster,  cocoon, 
and  caterpillar  are  shown  on  Plate  II,  d.  and  e. 

Though  the  gipsy  caterpillars  feed  upon  many  kinds  of  trees, 
shrubs,  and  plants,  they  seem  to  prefer  apple,  oak,  and  willow. 
Ash  is  nearly  exempt  from  injury.  The  remedies  are  to  spray  the 
foliage  with  lead  arsenate  in  May  and  June  to  kill  the  caterpillars, 
and  to  soak  the  egg-clusters,  whenever  found,  with  creosote  to 
prevent  hatching. 

(Bulletin  186). 


Fig.  14.    Oyster-shell  scale. 


European  Fruit  Lecaniuai  (Lecanium  corni  Bouche — 
anneniacum  Craw. ) 

This  European  scale  has  now  become  one  of  the  most  common 
of  all  the  brown  soft  scales  in  the  eastern  United  States.  Not 
only  does  it  attack  and  injure  fruit  trees,  but  also  rose,  blackberry, 
ash,  chestnut,  oak,  maple,  elm,  and  linden. 

This  is  a  reddish-brown  scale,  very  convex  in  shape,  and  the 
individuals  are  usually  thickly  clustered  on  one  side  of  the  stem. 
Each  reaches  a  diameter  of  about  one-eighth  of  an  inch.  The 
species  hibernates  on  the  twigs  in  a  partially  grown  condition. 
The  young  emerge  in  May  and  June.   (Shown  on  Plate  III,  b). 

This  scale  may  be  killed  by  dormant  sprays  of  lime-sulphur  and 
miscible  oils. 

(Report  for  1905,  page  237). 

Oyster-Shell  Scale  {Lepidosaphes  ulmi  Linn.) 

The  oyster-shell  scale  is  found  on  nearly  all  kinds  of  deciduous 
trees  and  shrubs,  and  even  occasionally  on  evergreen  species  like 
boxwood.  It  is  one  of  the  commonest  pests  of  nursery  stock  and 
occurs  particularly  on  apple,  ash,  birch,  lilac,  poplar,  walnut 
(Juglans),  and  willow. 


124  CONNECTICUT  EXPERIMENT  STATION  BULLETIN   292 

The  female  shells  are  long  and  narrow,  more  or  less  curved, 
and  about  the  same  color  as  the  bark.  They  are  shown  on  Plate 
III,  a,  and  in  Fig.  14.    Males  are  less  elongate  and  much  smaller. 

There  is  one  generation  each  year,  the  insect  passing  the  winter 
in  the  form  of  white,  oval  eggs  under  the  female  shells.  These 
eggs  are  laid  in  August  and  September  and  hatch  the  latter  part 
of  the  following  May. 

All  thoroughly  infested  trees  or  shrubs  or  branches  thereof 
should  be  removed  and  burned.  The  remaining  portions  should  be 
sprayed  while  dormant  with  liquid  lime-sulphur  (1-9)  or  with  a 
miscible  oil  (i  -  15).  Also  a  spray  of  40  per  cent  nicotine  solu- 
tion   (1-500)    about  June   10  will   readily  kill  the  young. 

(Report  for  1903,  page  229). 


INSECTS  INJURING  FRUIT  STOCK 
Key 

A.     Chewing  Insects  Devouring  Leaves  : 

1.  Forming  conspicuous  nests  or  webs  2 

Not  forming  prominent  nests  or  webs   3 

2.  Nests  in  crotches  of  apple  and  wild  cherry  in  May, 

Eastern  Tent  Caterpillar,  p.  125 
Nests  terminal,  July  to  September Fall  Webworm,  p.  120 

3.  Caterpillars  feeding  in  clusters  on  apple  4 

Caterpillars  feeding  singly  on  apple  5 

4.  Striped  lengthwise  with  brown  and  yellow ;   with   dorsal   spines 

and  prominent  red  hump  on  fourth  segment, 

Red-humped  Caterpillar,  p.  126 
Striped  lengthwise  with  brown  and  yellow;  with  slender  hairs 
and  with  yellow  cervical  shield, 

Yellow-necked  Caterpillar,  p.  127 

5.  Caterpillars  conspicuously  hairy    6 

Caterpillars  without  prominent  hairs    7 

6.  Gray  or  brown  caterpillars,  with  hairs  not  arranged  in  tufts ;  five 

pairs  of  blue  spots,  six  pairs  of  red  spots,     Gipsy  Moth,  p.  122 

Caterpillars  with  black,  white  or  buff  hairs  arranged  in  distinct 

tufts  and  pencils Tussock  Moths,  p.  121 

7.  Covered  by  a  thin  web  on  surface  of  leaf,  often  curling  it, 

Apple  and  Thorn  Skeletonizer,  p.  126 

Not  covered  by  web ;  green  or  gray,  smooth  larvae  which  loop 

in  crawling Cankerworms,  p.  120 

8.  Bright  green  beetles  with  coppery  wing-covers, 

Japanese  Beetle,  p.  127 
Smaller  tan-colored  beetles  with  long  sprawling  legs. 

Rose  Chafer,  p.  128 

9.  Brownish,    slimy   slugs    feeding  on   upper   surface   of   pear   and 

cherry  leaves   Pear  Slug,  p.  129 

Grayish   larvae   on   currant   and   gooseberry. 

Imported  Currant  Worm,  p.  129 


INSECT  PESTS  OF  NURSERY  STOCK  12^ 

10.  Caterpillars  injuring  buds   in  spring,  devouring  apple  buds  set 

the  preceding  summer Climbing  Cutworms,  p.  130 

Gray  snout  beetle  in  Alay  devouring  buds  of  the  new  growth  of 
pear  New  York  Weevil,  p.  131 

B.  Borers  in  Trunk  or  Branches  : 

11.  Large  larva,  white  with  black  spots,  tunneling  in  trunk  or  larger 

branches Leopard  Moth,  p.  120 

Larva   white,    without  black   spots,   tunneling   in   apple   trees   at 
base  of  trunk   12 

12.  With  broad  head,  making  gallery  under  the  bark, 

Fiat-headed  Apple  Borer,  p.  131 
With  cylindrical  head,  making  gallery  in  the  wood. 

Round-headed  Apple  Borer,  p.  131 

13.  Burrowing  in  tender  terminal  twigs  of  peach. 

Oriental  Peach  Aloth,  p.  132 
Burrowing  at  base  of  trunk^  of  peach Peach  Borer,  p.  132 

14.  Tunneling  at  base  of  twigs;  brood  chambers  under  the  bark; 

small  round  emergence  holes  in  bark..  .Shot-hole  Borer,  p.  133 
Tunnels  in  pith  of  currant  stems.  Imported  Currant  Borer,  p.  134 

C.  Sucking  Insects  on  Leaves,  Shoots,  or  Bark : 

15.  Greenish  aphids  on  apple  leaves  and  new  shoots. 

Green  Apple  Aphid,  p.  134 
Aphids  with  white  wax  secretion  on  apple  leaves  or  bark. 

Woolly  Apple  Aphid,  p.  135 

16.  Dark  brown  aphid  on  cherrj^,  curling  the  leaves. 

Black  Cherry  Aphid,  p.  136 
Green  aphid  on  currant,  blistering  the  leaves, 

Currant  Aphids,  p.  136 

17.  Small,  circular,  dark  gray  scale  insects  on  bark,   raised  nipple 

in  center San  Jose  Scale,  p.  137 

Elongated,  curved  scales,  same  color  as  bark. 

Oyster-shell  Scale,  p.  123 
Pear-shaped,    light   gray   scales    on   apple,   pear,   hawthorn,   and 

mountain  ash  Scurfy  Scale,  p.  137 

18.  Active,  greenish-white  insects  on  under  side  of  leaves,  causing 

white  peppered  appearance  on  upper  surface  of  apple. 

Leaf  Hoppers,  p.  138 
Grayish  bug  puncturing  tips  of  new  shoots,  dwarfing  and  dis- 
torting growth  Tarnished  Plant  Bug,  p.  139 

19.  Mites  causing  blisters  on  new  leaves  of  apple  and  pear. 

Pear  Leaf  Blister  Mite,  p.  140 

Red  mites  causing  apple  leaves  to  turn  brown  in  midsummer; 

winters  as  red  eggs  on  bark European  Red  ]\Iite,  p.  140 


Eastern  Tent  Caterpillar  {Malacosoma  avicricana  Fabr.) 

Makes  nests  or  tents  in  the  crotches  of  apple  and  wild  cherry 
trees  in  early  spring,  and  is  often  found  on  pear,  peach,  and  plum. 
This  is  a  one-generation  insect.  Caterpillars  reach  a  length  of 
about  two  inches  and  are  brown,  with  a  white  line  along  the  back, 
more  or  less  blue  along  the  sides  and  sparsely  covered  with  light 
brown  hairs.     They  feed  outside  the  nest  and  leave  a  strand  of 


126  CONNECTICUT  EXPERIMENT  STATION  BULLETIN   292 

silk  wherever  they  travel  along  a  twig  or  branch.  They  reach 
full  size  in  early  June,  crawl  about  for  a  few  days,  then  under 
rubbish  or  in  protected  places  spin  white,  oval  cocoons  about  an 
inch  long.  Two  weeks  later,  emerge  the  fawn-colored  moths 
which  fly  at  night,  mate,  and  the  females  during  July  lay  on  the 
twigs  clusters  of  eggs  which  hatch  the  following  April.  These 
clusters  are  in  the  form  of  cylinders  partially  or  entirely  encircling 
the  twigs,  and  covered  with  a  tough,  glue-like  substance  to  protect 
the  eggs.  Egg-mass,  caterpillars,  and  nest  are  shown  on  Plate  III, 
c,  d,  and  e. 

The  remedies  are :  Clip  off  and  burn  the  egg  clusters  during  the 
winter;  rub  off  the  nests  when  first  formed,  and  crush  the  young 
caterpillars  ;  spray  the  foliage  with  lead  arsenate. 

(Bulletin  177). 

Fall  Web  worm.     See  page  120 
Apple  and  Thorn  Skeletonizer  {Hemerophila  pariana  Clerck) 

For  the  past  few  years,  small,  slender  caterpillars  feeding  under 
webs  on  the  upper  surface  of  apple  leaves  have  been  rather  com- 
mon. It  is  a  European  pest  first  appearing  in  this  country  in 
Westchester  County,  New  York,  whence  it  has  spread  over  the 
New  England  States,  eastern  New  York  and  portions  of  New 
Jersey  and  Pennsylvania.  There  are  three  generations  each  year, 
with  a  partial  fourth  in  certain  seasons.  In  1923,  nearly  all  un- 
sprayed  apple  trees  in  central  Connecticut  were  skeletonized  and 
brown  in  July.  Since  then  it  has  subsided,  and  though  careful 
search  shows  it  to  be  present  in  nearly  every  orchard,  it  has  done 
little  harm  and  most  of  the  caterpillars  apparently  have  been 
either  parasitized  or  eaten  by  birds,  and  have  not  developed  to  the 
adult  stage.  Eggs  are  laid  singly  on  the  under  side  of  leaves.  The 
caterpillars  feed  at  first  on  the  lower  surface,  but  when  about  one- 
third  grown  they  move  to  the  upper  side  and  spin  a  light  web 
across  the  leaf,  often  curling  it,  and  feed  beneath  the  web.  White 
cocoons  are  often  made  on  the  leaves.  Injured  leaf  and  cocoon 
are  shown  on  Plate  IV,  a.  Apparently  the  insect  hibernates  in 
the  adult  form,  which  is  a  small  brownish  or  grayish  moth,  often 
with  purplish  tinge.  It  rests  on  window-screens  with  folded  wings, 
forming  a  triangle,  each  side  of  which  is  about  one-fourth  of  an 
inch. 

This  insect  is  easily  controlled  by  a  spray  of  lead  arsenate. 

(Bulletin  246). 

Cankerworms.     See  page  120 

Red-Humped  Caterpillar  {Schizura  concinna  S.  &  A.) 

In  late  summer,  curious  caterpillars  are  often  found  feeding  in 
clusters  on  young  apple  trees,  sometimes  defoliating  them.    These 


INSECT  PESTS  OF  NURSERY  STOCK  I27 

caterpillars  reach  a  length  of  one  and  one-half  inches  and  are 
striped  lengthwise  with  fine  lines  of  yellow,  black  and  white. 
Spines  are  borne  on  the  back,  but  these  are  longest  on  the  fourth 
segment,  which  is  dorsally  enlarged  and  a  bright  coral  red,  giving 
the  caterpillar  its  common  name.  Instead  of  resting  on  leaf  or 
stem  in  the  usual  position  of  most  caterpillars,  the  tail  end  of  the 
body  is  elevated,  as  shown  on  Plate  VI,  a.  The  adult  is  a  light 
brown  moth  with  a  wing  expanse  of  over  an  inch,  and  there  is 
only  one  brood  each  year.  The  pupae  live  in  the  ground  over 
winter. 

The  caterpillars  may  be  gathered  by  hand  and  destroyed,  or 
the  foliage  may  be  protected  with  a  spray-coating  of  lead  arsenate. 

(Bulletin  203,  and  Report  for  1917,  page  329). 

Yellow-Necked  Caterpillar   {Datana  niinistra  Drury) 

Another  caterpillar  which  feeds  in  clusters  on  apple  trees  in 
nurseries  and  young  orchards  in  late  summer  is  the  yellow-necked 
caterpillar.  When  fully  grown  it  is  nearly  two  inches  long  and  is 
striped  lengthwise  with  yellow  and  black  along  the  back.  Like 
other  caterpillars  of  the  genus  Datana,  when  disturbed  it  elevates 
head  and  tail,  as  shown  on  Plate  VI,  b.  Head  and  legs  are  black 
and  shining,  and  an  orange-yellow  cross  band  next  the  head  gives 
the  insect  its  name.  It  is  sparsely  covered  with  rather  short  and 
weak  light  brown  hairs.  Only  one  generation  occurs  each  year, 
the  winter  being  passed  by  the  pupae  in  the  ground. 

As  these  caterpillars  feed  mostly  on  young  trees  and  in  clusters, 
it  is  easy  to  remove  and  destroy  them,  or  the  foliage  may  be  pro- 
tected by  spraying  with  lead  arsenate. 

(Bulletin  203,  and  Report  for  1917,  page  328). 

Gipsy  Moth.     See  page  122 
Tussock  Moths.    See  page  121 

Japanese  Beetle  (PopilUa  japonica  Newman) 

This  insect  from  the  Orient  was  first  discovered  in  this  coun- 
try at  Riverton,  New  Jersey,  in  19 16.  Since  then  it  has  spread 
over  most  of  New  Jersey,  eastern  Pennsylvania,  western  Long 
Island  and  Westchester  County,  New  York,  into  Connecticut  as 
far  as  Bridgeport,  and  in  1927  it  was  found  in  Washington,  D.  C, 
and  at  several  points  in  Maryland. 

There  is  only  one  generation  each  season,  and  the  insect  passes 
the  winter  as  a  grub  or  larva  in  the  soil.  The  beetles  emerge  from 
June  15  to  August  15,  most  of  them  coming  out  in  July.  The 
grubs  feed  upon  grass  roots,  and  the  beetles  devour  the  foliage 
and  fruit  of  most  kinds  of  fruit  trees,  the  foliage  of  many  shade 


128 


CONNECTICUT   I':XPKKI.MENT   STATION 


BULLETIN   292 


trees  and  ornamental  shrubs,  as  well  as  the  flowers  and  leaves  of 
many  annual  and  perennial  plants.  Nursery  plants  with  soil  on  the 
roots  are  liable  to  contain  larvae,  and  if  not  treated,  they  may  be 
transported  in  this  manner.  The  beetle,  egg  and  grub  are  shown 
in  Fig.  15,  and  beetles  and  rose  leaves  injured  by  them  are  shown 
on  Plate  IV,  b.  and  c. 

The  remedies  are  :  treating  the  soil  with  carbon  disulphide  emul- 
sion ;  spraying  the  foliage  with  coated  lead  arsenate ;  spraying  the 
beetles  with  oleoresinate  of  pyrethrum.  It  is  a  difficult  pest  to 
control. 

(Report  for  1926,  page  244). 


Fig.  15.     The  Japanese  beetle,     a,  adult  beetle;  b,  grub  or  larva;  c,  egg. 
All  enlarged  about  five  times. 


The  Rose  Chafer  (Macrodactylus  subspinosus  Fabr.) 

The  rose  chafer  occurs  from  Canada  south  to  Virginia  and 
Tennessee  and  west  to  Colorado  and  Oklahoma.  The  region  of 
its  greatest  abundance,  and  therefore  of  its  greatest  destructive- 
ness,  is  in  southern  New  England  and  the  Middle  Atlantic  States. 

The  injury  to  the  foliage  and  fruit  is  done  by  the  adult  beetle. 
The  rose  chafer  is  a  yellowish-brown  beetle  about  one-third  of  an 
inch  long  and  with  long  sprawling  legs.  The  larva  or  grub  is 
yellowish-white  with  pale  brown  head ;  it  lives  in  the  ground  and 
is  rarely  seen.  The  adult  beetles  feed  upon  the  leaves  of  a  num- 
ber of  plants,  as  well  as  flowers  and  fruit.  They  are  very  fond 
of  grape  blossoms  and  newly  set  fruit,  often  destroying  the  entire 
crop.  Roses  and  peonies,  especially  the  light-colored  varieties,  are 
often  ruined  by  this  insect.  In  nurseries  grape  leaves  are  some- 
times partly  eaten.  Hydrangeas  were  injured  quite  severely  in 
1927.  The  work  of  this  insect  is  shown  in  Fig.  16,  and  on  Plate 
V,  a. 

The  beetles  emerge  from  the  ground  and  attack  the  plants  usu- 
ally about  the  second  week  in  June  in  Connecticut.  Soon  after 
emerging,  the  beetles  mate,  and  the  female  lays  her  eggs  singly  in 


INSECT  PESTS  OF  NURSERY  STOCK 


129 


the  ground,  usually  depositing  from  24  to  36  eggs.  These  eggs 
soon  hatch,  and  the  young  larvae  feed  on  the  roots  of  grass  and 
other  plants  until  fall,  when  they  descend  deeper  into  the  soil 
below  the  frost  line.  In  the  spring  the  grubs  ascend,  transform 
to  pupae  in  earthen  cells,  and  the  beetles  emerge  two  to  four 
weeks  later. 

The  rose  chafer  is  an  exceedingly  difficult  insect  to  control  by 
ordinary  measures.  The  best  remedy  known  is  to  cover  the  foli- 
age with  a  heavy  application  of  arsenate  of  lead.  In  vineyards, 
hand  picking  is  sometimes  recommended  to  protect  the  blossoms 


Fig.  16.    Rose  chafer. 

and  newly  set  fruit  from  being  eaten  by  this  insect.  In  New 
Jersey,  self-boiled  lime-sulphur  is  an  effective  repellent  on  fruit 
trees. 

(Report  for  1916,  page  in). 

The  Pear  Slug  (Eriocampoides  limacina  Ratz. ;  Caliroa  cerasi 

Linn.) 

In  late  summer  the  leaves  of  pear  stock  are  often  eaten  by  soft, 
slimy,  brown,  slug-like  worms  which  feed  upon  the  upper  sur- 
face. Cherry  leaves  are  likewise  injured.  This  has  been  called  the 
cherry  and  pear  slug,  and  several  scientific  names  have  also  been 
applied  to  it.  It  is  the  larva  of  a  sawfly,  and  there  are  two  gen- 
erations each  season.    This  insect  is  shown  in  Fig.  17. 

The  pest  is  easily  controlled  by  spraying  or  dusting  with  lead 
arsenate  or  fresh  hellebore. 

(Report  for  1920,  page  199). 


Imported  Currant  Worm   (Ftcronidea  ribcsi  Scop.) 

This  insect  often  defoliates  currant  and  gooseberry  bushes  in 
nurseries.  The  adults  of  the  currant  worm  spend  the  winter 
months  in  the  ground  and  emerge  during  the  latter  part  of  April 
or  early  May.  They  lay  their  eggs  on  the  under  side  of  the  leaves. 
In  about  a  week  or  ten  days  the  eggs  hatch,  and  the  young  larv^ae 


I30 


CONNECTICUT  EXPERIMENT  STATION 


BULLETIN   292 


begin  to  feed  on  the  tender  leaves.  After  they  are  full  grown, 
they  enter  the  ground  and  spin  small  brown  cocoons,  from  which 
the  adults  for  the  second  brood  emerge.     Shown  in  Fig.  18. 

The  control  measures  for  this  insect  are  very  simple.  Usually 
one  application  of  arsenate  of  lead,  either  in  the  form  of  dust  or 
spray,  will  hold  it  in  check.  If  the  fruit  is  to  be  picked  and  sold, 
it  is  better  to  dust  the  plants  with  hellebore,  as  this  soon  washes 
off  and  is  not  so  poisonous  to  man  as  arsenate  of  lead. 

(Report  for  1902,  page  170). 

Climbing  Cutworms 

Apple  trees  in  nursery  rows  and  in  newly  set  orchards  have 
been  injured  in  Connecticut  by  climbing  cutworms.  In  May,  1925, 
on  apple  stock  in  Durham,  the  buds  which  had  been  set  the  preced- 


FiG.  17.  Pear  slug,  a,  adult  sawfly,  female;  b,  larva  with  slime  removed; 
c,  larva  in  normal  state;  d,  leaves  and  larvae,  natural  size;  a,  b,  c, 
much  enlarged.  (After  Marlatt,  Circular  26,  Division  of  Entomol- 
ogy>  U.  S.  Department  of  Agriculture). 


ing  summer  were  eaten  off  (see  Plate  VI,  c),  and  raspberry  plants 
near  by  had  also  been  stripped.  Two  species  of  cutworms  were 
responsible,  and  when  reared,  the  adults  proved  to  be  Agrotis  uni- 
color  Walker  (formerly  Noctua  eland estina  Harris)  and  Noctua 
fennica  Tausch.  In  May,  1926,  similar  injury  occurred  on  grafts 
set  in  young  orchard  trees  in  Wallingford,  and  was  caused  by  the 
dingy  cutworm,  Fcltia  subgotJiica  Haworth.  In  May,  1922,  rasp- 
berries in  East  Haven  were  injured  by  cutworms,  and  from  the 
material  two  moths  were  reared,  Par  agrotis  messoria  Harris  and 
P.  tessellatus  Harris.    The  same  season  larvae  of  Noctua  c-nigrmn 


INSECT  PESTS  OF  NURSERY  STOCK 


131 


Linn,  injured  strawberry  plants  in  a  field  near  New  Haven.  As 
the  injury  is  seldom  noticed  until  too  late,  treatment  is  ineffec- 
tive. In  certain  cases  a  liberal  application  of  lead  arsenate  may 
protect  the  plants. 

(Bulletin  247,  and  Report  for  1922,  pages  373,  375  ;  Bulletin  275 
and  Report  for  1925,  page  324;  Bulletin  285,  and  Report  for  1926, 
page  2,^6). 

New  York  Weevil  {ItJiycerus  noveboracensis  Forst.) 

Though  the  injury  is  not  common,  occasionally  young  pear  and 
plum  trees  are  injured  by  this  weevil,  which  eats  into  the  bases  of 
new  shoots,  sometimes  nearly  severing  them.  In  a  young  orchard 
in  Wallingford  in  1908,  injury  by  this  weevil  was  quite  prominent 


Fig.  18.    Imported  currant  worm.         Fig.  19.     Round-headed  borer. 


the  last  week  in  May.  The  insect  is  a  snout  beetle  about  half  an 
inch  in  length,  gray  or  slightly  reddish,  marked  with  quadrate 
black  spots. 

Spraying  with  lead  arsenate  proved  an  effective  remedy. 

(Report  for  1908,  page  845). 

Leopard  Moth.     See  page  120 

Apple  Tree  Borers 

There  are  two  common  species  of  borers  which  attack  apple 
trees  in  Connecticut.  They  are  known  as  the  flat-  and  round- 
headed  borers. 

The  round-headed  borer,  Saperda  Candida  Fabr.,  usually  attacks 
the  main  trunk  of  the  trees  near  the  base.  The  adult  is  one  of  the 
long-horricd  beetles  and  may  be  easily  recognized  by  two  straight 
white  lines  running  lengthwise  on  its  back  (see  Fig.  19).  The 
eggs  are  laid  during  the  summer,  and  the  young  borers  tunnel  just 


132  CONNECTICUT   EXPERIMENT   STATION  BULLETIN   292 

under  the  bark  until  winter.  The  following  year  they  tunnel  into 
the  sapwood  and  the  third  year  feed  directly  in  the  solid  wood. 
By  this  time  the  borers  are  quite  large  and  do  much  damage  to 
young  trees,  often  killing  them.  The  best  remedy  is  to  cut  them 
Out  with  a  knife.  Often  a  wire  with  a  barb  near  the  end  is  very 
useful  to  push  into  the  tunnels  and  draw  out  the  borers.  The 
insect  sometimes  attacks  other  trees  beside  apple,  quince  being  a 
favorite  host,  as  well  as  Crataegus  and  mountain  ash.  The  pres- 
ence of  borers  may  be  noted  by  sawdust  on  the  ground  at  the  base 
of  trees,  which  the  borers  have  pushed  from  their  burrows. 
(Report  for  1907,  page  333). 

The  flat-headed  apple  tree  borer  is  the  larva  of  a  Buprestid  bee- 
tle, CJirysobothris  fcmorata  Fabr.  As  a  rule,  this  insect  attacks 
only  trees  that  have  been  weakened  by  some  other  cause.  It  attacks 
a  large  variety  of  trees  and  has  often  been  found  in  dry  cordwood. 

The  borer  seldom  produces  any  visible  castings,  but  its  presence 
may  be  noted  by  a  darkened  and  depressed  area  over  the  gallery. 
The  larva  when  full  grown  is  about  an  inch  long  and  has  a  broad, 
flat  head,  from  which  it  derives  its  name.  It  normally  lives  but  one 
year  in  the  tree,  although  under  certain  conditions  it  may  live  two 
years. 

The  remedy  is  to  cut  out  borers  when  found  and  to  keep  trees 
in  good  condition  by  proper  cultivation  and  fertilization. 

(U.  S.  Farmers'  Bulletin  1270,  page  73). 


Oriental  Peach  Moth    (Laspeyresia  molesta  Busck) 

This  pest  from  the  Orient  is  believed  to  have  been  brought  into 
the  United  States  on  flowering  cherries  from  Japan  and  has  now 
spread  throughout  the  Atlantic  States  as  far  north  as  Massachu- 
setts and  as  far  west  as  the  Mississippi  River.  It  has  also  beer 
found  in  Ontario,  Canada.  There  are  three  generations  each  sea- 
son, and  the  larvae  live  through  the  winter  in  inconspicuous  cases 
on  the  bark.  The  larvae  tunnel  in  the  twigs  (see  Plate  V.  b). 
causing  the  tips  to  die  and  the  lateral  buds  to  develop  and  form 
thick  bushy  tops.  Though  primarily  an  orchard  pest,  it  often  at- 
tacks nursery  trees.    No  good  remedies  are  known. 

(Reports  for  1925,  page  280;  1926,  page  234). 

Peach  Borer  (Synanthedon  exitiosa  Say) 

The  adult  of  the  peach  borer  is  a  wasplike  moth.  It  lays  its 
eggs  in  midsummer,  and  the  borers  hatching  from  then  live  in 
the  trunks  and  often  the  larger  roots  until  the  following  June  or 
Juty,  when  they  pupate  in  their  burrows.  The  adults  emerge  to 
lay  eggs  for  the  next  generation.  This  borer  is  sho\rn  on  Plate 
VI,  d. 


INSECT  PESTS  OF  NURSEKV  STOCK 


133 


The  only  satisfactory  remedy  on  nursery  trees  is  to  cut  open  the 
burrows  and  kill  the  borers.  A  small  piece  of  wire  is  very  useful 
to  insert  into  the  burrows  to  pull  the  borers  out,  saving  consider- 
able cutting  of  the  trunk  of  the  tree.  The  injury  may  easily  be 
seen  by  masses  of  gum  at  the  base  of  the  tree.  This  gum  is  often 
full  of  small  particles  of  wood  which  the  borer  pushes  from  the 
burrow.  Older  peach  trees  may  be  treated  with  paradichloroben- 
zene,  but  this  treatment  is  not  safe  on  nursery  trees. 

(Report  for  1909,  page  359). 


Shot  Hole  Borer   {Scolytus  rugiilosus  Ratz.) 

This  insect  attacks  most  of  the  fruit  trees  which  are  normally 
grown  in  Connecticut.  The  injury  is  caused  by  the  larva  of  a 
small  beetle  which  lays  its  eggs  under  the  bark  of  weakened  and 
sickly  trees,  rarely  attacking  vigorous,  healthy  trees.     The  eggs 


Fig.  20.    Shot-hole  borer. 


hatch  into  small  white  grubs  which  bore  just  under  the  bark  and 
slightly  into  the  wood.  The  larvae  live  over  the  winter  in  these 
galleries  and  during  the  following  summer  transform  to  the  adult 
stage  and  emerge  from  the  trees,  leaving  small  round  holes  in  the 
bark.  The  bark  of  the  infested  trees  looks  as  though  it  had  been 
riddled  by  shot,  and  this  fact  gives  the  insect  its  common  name. 
Occasionally  the  beetles  tunnel  at  the  base  of  small  twigs,  which 
may  weaken  the  tree  to  such  an  extent  that  the  grubs  may  live 
under  the  bark.    This  insect  is  shown  in  Fig.  20. 

The  only  remedy  is  to  cut  out  infested  trees  or  branches  and 
burn.  Much  can  be  done  to  prevent  injury  by  removing  sickly 
trees  in  or  near  the  nursery  and  keeping  all  fruit  stock  in  a  vig- 


134 


CONNECTICUT   EXPERIMENT   STATION 


BULLETIN   292 


orous  growing  condition  by  the  application  of   nitrogenous   fer- 
tilizer and  by  cultivation. 

Imported  Currant  Borer  {Sesia  tipuliformis  Clerck) 

The  adult  is  a  clear- wing  moth  which  appears  in  June,  and  the 
female  lays  eggs  singly  on  the  bark.  The  young  larvae  enter  the 
stem  and  bore  upward  or  downward  in  the  pith,  kilHng  the  stem. 
They  are  nearly  full  grown  when  winter  approaches  and  hibernate 
in  the  burrows.  The  following  May,  each  larva  tunnels  outward 
but  leaves  the  burrow  covered  by  a  thin  layer  of  bark.  It  then 
pupates  in  the  burrow,  and  in  June  the  moth  emerges,  leaving  the 
pupa  skin  projecting  from  the  cavity.  There  is  only  one  brood 
each  season.  Infested  canes  appear  sickly  and  should  be  cut  oft 
and  burned  before  June  i  to  kill  the  borers  before  the  moths 
emerge. 

(Fruit  Insects,  page  339). 


Fig. 


21.    Green  apple  aphid.    Eggs  011 
twig;  aphids  on  leaf. 


Green  Apple  Aphid  (Aphis  point  DeG.) 

This  insect  probably  causes  more  injury  to  apple  trees  in  the 
nursery  than  any  other  insect  attacking  apple  trees  in  Connecticut. 
This  was  particularly  true  during  the  early  summer  of  1927,  when 
these  insects  were  very  numerous  and  caused  much  injury  by 
stopping  growth  and  distorting  young  apple  trees  in  Connecticut 
nurseries. 

The  insect  passes  the  winter  in  eggs  laid  on  twigs.  The  eggs 
are  yellowish-green  when  laid,  becoming  glossy  black.  The  young 
aphids  hatch  early  in  the  spring,  as  soon  as  the  buds  begin  to  open, 
and  start  to  feed  on  the  young,  unfolding  leaves.  No  eggs  are  laid 
during  the  summer  generations,  the  young  aphids  being  born  alive, 
and  are  ready  to  feed  immediately.    There  are  from  9  to  17  broods 


INSECT  PESTS  OF  NURSERY  STOCK  135 

produced  during  the  season,  following  which  the  sexual  individuals 
appear  and  deposit  the  overwintering  eggs.  This  aphid  is  shown 
on  Plate  VII,  b,  and  in  Fig.  21. 

Thorough  spraying  of  the  trees  when  the  buds  are  opening  in 
spring,  using  lime  and  sulphur  at  the  rate  of  one  part  to  nine 
parts  of  water,  plus  one  pint  of  nicotine  sulphate  to  every  one 
hundred  gallons  of  water,  will  be  found  of  great  value.  Some  of 
the  miscible  oils  are  also  very  good  for  this  purpose,  if  the  direc- 
tions of  the  manufacturers  are  followed.  Spraying  at  this  time 
with  either  of  these  sprays  will  also  help  in  the  control  of  San 
Jose  scale.  During  the  summer,  after  the  leaves  have  become 
curled,  it  is  almost  impossible  to  hit  the  aphids  with  any  sprays. 
It  is  therefore  necessary  to  dip  the  tips  of  the  branches — where 
most  of  the  aphids  are  found — in  a  pail  of  spray  material  con- 
sisting of  one  pint  of  nicotine  sulphate  to  one  hundred  gallons 
water.  It  is  very  important  that  about  four  pounds  of  soap,  pre- 
viously dissolved  in  hot  water,  be  added  to  the  mixture.  Other 
aphids  may  often  be  found  on  apple  stock,  but  the  above  treatment 
is  effective  on  all  kinds  of  plant  lice. 


Woolly  Apple  Aphid  {Eriosoma  lanigcrum  Haus.) 

This  aphid  differs  from  other  aphids  in  the  fact  that  it  attacks 
its  host  plants  both  above  and  below  the  ground,  and  those  that  are 
above  ground  are  covered  by  a  white  wax  secretion  resembling 
cotton  (see  Plate  VII,  c).  These  aphids  often  cluster  in  wounds, 
such  as  scars,  cankers,  and  other  injuries.  The  root  form  of  this 
insect  causes  the  roots  to  be  deformed  and  covered  with  small 
galls. 

The  life  history  of  this  aphid  is  rather  intricate  but  may  be 
briefly  outlined  as  follows :  The  eggs  are  laid  in  the  crevices  of 
the  bark  on  elm  trees  in  September  and  hatch  in  early  spring.  The 
aphids  hatching  from  these  eggs  are  wingless  females  and  their 
young  are  also  wingless,  but  the  next  brood  produces  winged  adults 
which  migrate  to  apple  and  somiCtimes  to  pear,  quince,  mountain 
ash  and  Crataegus.  There  are  three  summer  broods,  and  in  Au- 
gust winged  females  appear  which  migrate  back  to  elm  and  lay 
winter  eggs. 

The  aerial  form  may  be  controlled  by  spraying  with  kerosene 
emulsion  or  with  nicotine  sulphate  and  soap.  The  underground 
forms  are  harder  to  kill,  as  it  is  almost  impossible  to  make  spray 
permeate  the  ground  sufficiently  to  kill  the  aphids.  Carbon  disul- 
phide  emulsion  has  been  used  with  some  success.  One-half  pound 
of  carbon  disulphide  emulsion  in  four  gallons  of  water  poured  into 
a  shallow  trench  around  the  trees  will  kill  the  underground  forms. 

(Report  for  1924,  page  308). 


136  CONNKCTICL'T   EXPICRI.M  KNT   S'lATION  BULLETIN   292 

Black  Cherry  Aphid  {Myzus  cerasi  Fabr.) 

The  black  cherry  aphid  is  often  very  abundant  on  sweet  cherry 
stock  in  nurseries.  It  is  a  black  insect  with  a  rounded  abdomen, 
giving  it  a  more  or  less  globular  appearance. 

The  eggs  are  laid  upon  cherry  twigs  in  the  fall  and  hatch  early 
in  the  spring,  often  before  the  cherry  buds  open.  They  are  able 
to  withstand  freezing,  and  as  soon  as  warm  weather  comes  and  the 
buds  open,  they  begin  to  feed  and  reproduce.  This  usually  takes 
place  in  two  or  three  weeks.  Later  broods  become  mature  in  less 
than  a  week.  Some  of  the  individuals  of  the  later  broods  become 
winged  and  migrate  to  pepper  grass,  where  they  continue  to  repro- 
duce until  fall.  They  then  migrate  back  to  cherry  and  lay  the  over- 
wintering eggs.  Not  all  of  the  aphids  migrate  from  cherry,  and 
some  can  usually  be  found  on  it  all  summer,  although  during 
the  latter  part  of  the  season  they  may  not  be  very  plentiful. 

Control  measures  given  for  green  apple  aphids  will  be  found 
useful  for  the  cherry  aphids.     (See  page  135). 

(U.  S.  Farmers'  Bulletin  1128,  page  20). 


Currant  Aphids 

There  are  several  species  of  aphids  causing  injury  to  currant 
foliage.  Their  life  histories  are  very  similar  and  the  same  control 
measures  would  be  equally  effective  on  all  species. 

Perhaps  the  most  common  species  in  Connecticut  is  called  the 
currant  aphid,  Myzus  ribis  Linn.,  which  causes  the  terminal  leaves 
to  become  much  distorted,  and  little  pits  or  pockets  are  formed 
on  the  under  side  of  the  leaves.  The  upper  surface  becomes  more 
or  less  reddish  m  color,  which  is  noticeable  some  distance  away. 
When  plants  are  heavily  infested,  these  leaves  fall,  causing  the 
plants  to  make  a  poorer  growth. 

The  stem  mothers  hatch  from  eggs  on  currant  twigs  soon  after 
the  leaves  develop  in  spring.  Some  of  the  young  from  the  stem 
mothers  develop  wings  and  migrate  to  motherwort,  hedge-nettle, 
and  other  related  plants.  The  wingless  forms  remain  on  currants 
and  continue  reproduction.  In  each  generation  some  winged  in- 
dividuals appear  which  migrate,  but  v/ingless  forms  are  found  on 
bushes  until  late  summer.  Early  in  October,  migrants  return  and 
deposit  the  sexual  females,  which.  wlT,en  mature,  mate  with  the 
winged  males,  and  eggs  are  laid  upon  the  twigs. 

Spraying  with  nicotine  sulphate  and  soap  when  the  buds  are 
opening  will  kill  the  stem  mothers,  or  a  later  spray  of  the  same 
material,  directed  upward  to  hit  the  aphids  on  the  under  side  of 
the  leaves,  will  hold  the  insects  in  check. 

(U.  S.  Farmers'  Bulletin  1128,  page  28). 


INSECT  PESTS  OF  NURSERY  STOCK  137 

San  Jose;  Scale  (Aspidiotiis  perniciosus  Comst.) 

A  number  of  years  ago  this  insect  was  considered  one  of  the 
most  destructive  scales  infesting  nursery  stock.  It  is  thought  to 
have  been  introduced  from  China  and  was  first  found  in  this  coun- 
try in  San  Jose,  CaHfornia,  about  1870.  Since  that  time  it  has 
been  spread  through  the  principal  fruit  and  nursery  districts  of  the 
United  States. 

The  general  use  of  dormant  and  summer  sprays,  together  with 
its  natural  enemies,  has  so  reduced  its  numbers  that  it  is  not  con- 
sidered so  serious  a  menace  as  formerly.  Occasionally,  however, 
nursery  trees  are  nearly  killed  by  this  insect.  This  is  particularly 
true  of  fruit  stock  which  has  been  heeled  in  for  a  few  years ;  it 
invariably  becomes  infested  with  scale  and  must  be  destroyed. 
Apple,  pear,  and  peach  trees  are  its  favorite  food  plants,  but  other 
fruit  trees,  as  well  as  shrubs  and  shade  trees,  are  often  attacked. 

The  scale  or  covering  beneath  which  the  insect  lives  is  circular, 
about  the  size  of  a  pin-head,  grayish  in  color,  with  the  central  por- 
tion raised,  and  is  shown  in  Fig.  22,  and  on  Plate  VII,  a. 

The  best  method  of  control  is  to  spray  the  trees  while  dormant 
with  a  lime-sulphur  solution,  using  one  part  to  nine  parts  of  wa- 
ter, or  with  one  of  the  many  miscible  oils  now  on  the  market,  fol- 
lowing the  manufacturer's  directions. 

(U.  S.  Farmers'  Bulletin  1270,  page  62). 


Oyster-Shell  Scale.     See  page  123 


Scurfy  Scale    {Chionaspis  furfura   Fitch) 

Apple  and  pear  trees,  as  well  as  other  common  deciduous  trees 
and  bush  fruits,  are  often  attacked  by  the  scurfy  scale,  which  re- 
tards the  growth  and  sometimes  causes  the  death  of  the  trees  if 
the  infestation  is  severe.  This  insect  is  a  native  of  the  United 
States,  but  is  most  common  in  the  New  England  and  Middle  At- 
lantic States.  It  is  easily  recognized  by  its  dirty-white  color  and 
pear-shaped  scale  in  the  female,  and  the  white  elongated  scale  of 
the  male,  as  shown  on  Plate  VII,  f. 

The  insect  winters  in  the  egg  stage,  the  eggs  being  found  under 
the  female  scales.  The  eggs  and  the  young  scales  are  purplish, 
tinted  with  red,  and  hatch  the  last  week  of  May.  In  the  North 
there  is  but  one  brood  each  season,  but  farther  south  there  may  be 
two  or  three  broods. 

A  dormant  spray  of  lime  and  sulphuf,  or  a  miscible  oil,  applied 
as  for  San  Jose  scale,  will  usually  control  the  scurfy  scale. 

(U.  S.  Farmers'  Bulletin  1270,  page  65). 


138 


CONNECTICUT  EXPERIMENT  STATION 


BULLETIN   292 


Leaf  Hoppers  on  Apple 

There  are  two  species  of  leaf  hoppers  commonly  found  on  apple 
stock  in  Connecticut  nurseries.  They  are  quite  similar  in  appear- 
ance but  their  life  histories,  as  well  as  the  injury  they  cause  to 
growing-  apple  trees,  are  quite  different. 

The  leaf  hopper  causing  the  most  injury  to  young  apple  trees  is 
known  as  the  apple  leaf  hopper,  Empoasca  mali  LeBaron,  shown 
in  Fig.  23.  The  other  is  commonly  known  as  the  rose  leaf  hop- 
per, Empoa  rosae  Linn.  The  injury  caused  by  the  former  is  very 
noticeable  on  young  trees,  where  it  attacks  the  tender  terminal 
leaves,  causing  them  to  become  reduced  in  size,  curled,  and  mis- 
shapen. The  effect  of  feeding  by  the  insects  is  to  make  the  tips 
and  edges  of  the  leaves  brown  and  dry. 


Fig.  22.     San  Jose  scale. 


Fig.  23.  The  apple  leaf  hopper,  in  its 
different  stages.  (After  Wash- 
burn, 9th  Report  State  Entomolo- 
gist of  Minnesota). 


The  life  history  of  the  apple  leaf  hopper  is  as  follows :  The 
adults  pass  the  winter  under  fallen  leaves  or  any  other  convenient 
shelter.  When  the  weather  becomes  warm  in  the  spring,  they 
leave  their  hibernating  quarters  and  go  to  the  young  apple  leaves 
to  feed.  Later  the  eggs  are  laid  under  the  lower  epidermis  of  the 
leaves  and  hatch  in  a  short  time.  Three  generations  are  pro- 
duced each  year,  the  last,  one  hibernating. 

The  so-called  rose  leaf  hopper  makes  the  apple  leaves  appear 
more  or  less  stippled  or  mottled.  Leaves  seriously  infested  by  this 
insect  are  unable  to  function  properly,  and  in  extreme  cases  fall 
to  the  ground,  interfering  with  the  proper  growth  of  the  trees. 

This  insect  is  believed  to  have  been  introduced  from  Europe, 
perhaps  on  nursery  stock,  and  is  now  widely  distributed  through- 
out the  United  States.  Among  its  food  plants,  besides  apple,  are 
grape,  raspberry,  currant,  gooseberry,  blackberry,  elm,  oak,  and 
others,  though  rosaceous  plants  are  preferred. 


INSECT  PESTS  OF  NURSERY  STOCK  1 39 

The  leaf  hopper  passes  the  winter  in  the  egg  stage.  The  eggs 
are  deposited  beneath  the  bark  of  apple  and  rose,  producing  tiny, 
raised,  blister-like  spots.  They  hatch  in  early  spring,  and  the 
young  are  mature  early  in  summer.  The  eggs  for  the  second 
brood  are  deposited  in  the  veins  of  the  leaves.  There  are  two 
broods  each  season. 

Control  measures  are  the  same  for  both  species :  A  spray  of  one 
pint  of  nicotine  sulphate  in  a  hundred  gallons  of  water  in  which 
four  pounds  of  soap  have  been  dissolved  will  be  found  very  effec- 
tive if  applied  when  the  first  generation  is  still  young.  The  spray 
must  strike  the  underside  of  the  leaves  where  the  young  leafhop- 
pers  feed. 

(U.  S.  Farmers'  Bulletin  1128,  page  26). 

Tarnished  Plant  Bug  (Lygns  pratensis  Linn.) 

This  insect  injures  peach  stock  by  puncturing  the  tip  of  the 
tender  new  shoots,  sucking  out  the  juices,  and  probably  injecting 


Fig.  24.  Tarnished  plant  bug:  adult  at  left:  last  stage  of  nymph  at  right. 
Enlarged  about  four  times.  (After  Chittenden,  Bulletin  43,  Bureau 
of  Entomolog)',  U.  S.  Department  of  Agriculture). 

some  poisonous  substance  into  the  tissues,  which  soon  die.  This 
injury  is  called  "stop-back"  or  "bush-head."  Pear  and  apple  trees, 
and  many  flowering  plants  are  also  injured  by  the  tarnished  plant 
bug.  The  female  lays  eggs  in  the  tender  shoots  or  in  the  petioles 
or  veins  of  the  leaves.  The  young  bugs  are  yellowish-green  and 
pass  through  five  stages  before  the  mature  winged  form  appears. 
Both  nymph  and  adult  are  shown  in  Fig.  24.  There  are  probably 
several  generations  each  year,  and  all  stages  may  be  found  from 
May  until  November. 

All  weeds  and  rubbish  around  the  field  should  be  destroyed  by 
burning  or  plowing.  Spraying  heavily  with  nicotine  solution  and 
soap  will  probably  kill  the  nymphs. 

(Missouri  Bulletin  i/O,  page  17). 


140  CONNECTICUT  EXPIvKI.M  1-:NT   STATION  BULLE^TIN   292 

Pear  Leaf  Blister  Mite  (Eriopliyes  pyri  Pag.) 

The  pear  blister  mite  attacks  the  foHage  of  apple  and  pear  but 
rarely  causes  any  serious  injury  to  apple  foliage.  On  pear  it  is 
often  a  serious  pest,  causing"  a  slowing  up  of  tree  growth,  making 
undersized  pear  stock.  It  produces  on  the  foliage  small  reddish 
or  greenish  galls  or  blisters  which,  after  a  time,  turn  brown, 
spotting  the  leaves  with  dead  areas,  as  shown  on  Plate  VII,  e. 
When  the  galls  are  abundant,  the  tissues  become  dead,  and  the 
injured  leaves  have  a  brownish,  shriveled  appearance  and  often 
drop. 

This  mite  is  of  European  origin,  but  is  now  widely  distributed 
wherever  pears  are  grown. 

The  winter  is  passed  in  the  adult  stage  under  the  bud  scales. 
The  adults  are  very  small,  elongate,  whitish  insects.  In  spring 
when  the  leaves  are  unfolding,  the  mites  enter  the  leaves  through 
the  lower  epidermis,  and  their  activities  soon  produce  their  char- 
acteristic galls,  in  which  they  live  and  multiply.  After  reaching 
maturity,  the  mites  desert  the  old  galls,  make  new  ones,  and  pro- 
duce a  new  generation.  The  process  continues  until  cold  weather, 
when  the  adults  migrate. to  the  bud  scales  for  the  winter. 

Spraying  while  the  trees  are  dormant  with  lime-sulphur  solution 
as  for  San  Jose  scale  will  hold  this  mite  in  check.  Summer  sprays 
are  of  doubtful  value,  the  mites  being  inside  the  leaves  and  pro- 
tected from  the  action  of  the  sprays. 

(Report  for  19 lo,  page  700). 

European  Red  Mite  (Paratetranychus  pilosus  Can.  &  Fanz.) 

The  work  of  the  European  red  mite  was  first  noticed  on  orchard 
trees  in  Connecticut  in  1920.  Since  then  it  has  caused  consider- 
able injury  to  orchard  trees  throughout  the  State. 

The  presence  of  mites  on  the  foliage  is  usually  indicated  by  the 
leaves  turning  brown,  if  the  infestation  is  severe.  A  light  in- 
festation gives  the  foliage  a  sickly  color  and  interferes  with  the 
proper  functioning  of  the  leaves. 

The  mite  has  been  found  on  apple,  cherry,  plum,  peach,  pear, 
rose,  and  elm,  although  most  of  the  real  injury  in  Connecticut  has 
been  noticed  on  apple. 

The  eggs  of  the  European  red  mite  may  be  found  on  the  branch- 
es and  twigs  of  infested  trees  during  the  late  fall  and  winter,  as 
are  shown  on  Plate  VII,  d.  They  are  reddish  in  color  and  .15  mm. 
in  diameter.  When  plentiful,  they  give  the  twigs  the  appear- 
ance of  being  covered  with  brick  dust.  The  eggs  hatch  dur- 
ing the  latter  part  of  April  or  early  in  May,  and  the  young  mites 
make  their  way  to  the  young  leaves,  where  they  begin  to  feed. 
They  reach  maturity  in  about  three  weeks  and  begin  to  lay  eggs 
for  the  next  brood.     There  are  several  broods  in  a  season. 


INSECT  PESTS  OF  jN'URSERY  STOCK  I4I 

The  best-known  remedy  is  to  spray  in  early  spring,  just  before 
the  eggs  hatch,  with  one  of  the  miscible  oils.  Lime-sulphur  may 
be  used,  but  is  not  as  effective  as  an  oil  spray.  Care  must  be 
taken  to  spray  thoroughly,  hitting  all  the  eggs.  If  many  of  the 
eggs  are  missed  in  spraying,  they  will  hatch  and  breed  fast  enough, 
under  favorable  conditions,  to  give  rise  to  a  serious  infestation 
later  in  the  summer.  If  mites  become  plentiful  during  the  sum- 
mer, a  spraying  of  linseed  oil  emulsion  will  be  effective,  using 
one  gallon  of  linseed  oil  and  one  and  one-quarter  pounds  of  soap 
to  one  hundred  gallons  of  water. 

(Bulletin  252). 


INSECTS  INJURING  DECIDUOUS  SHADE  AND 
FOREST  TREES 

Key 

A.     Feeding  upon  the  leaves : 

1.  Mining  in  leaves  of  larch Larch  Case  Bearer,  p.  142 

Mining  in  leaves  of  locust Locust  Leaf  Miner,  p.  143 

Making  blotch  mines  in  birch  leaves. 

Imported  Birch  Leaf  ]Miner,  p.  143 

2.  Skeletonizing  the  leaves    3 

Devouring  the  leaves,  except  the  larger  veins  5 

3.  On  poplar  and  willow  4 

On  birch  Birch  Skeletonizer,  p.  144 

On  elm  Elm  Leaf  Beetle,  p.  144 

4.  Small,   dark  blue  or  green  beetles ;   mostly  bright  green,  2-4  mm. 

long Willow  Flea  Beetle,  p.  145 

Mostly  dull  blue,  4-5  mm.  long. 

Imported  Willow  Leaf  Beetle,  p.  145 
Larger   beetles,    7-10   mm.   long,    light   brown,    marked   with   black 

longitudinal  lines,  on  poplar Cottonwood  Leaf  Beetle,  p.  145 

Marked  in  the  form,  of  irregular  black  dots, 

Spotted  Willow  Leaf  Bettle,  p.  145 

5.  Forming  webs  or  nests  6 

Not  forming  webs  or  nests  7 

6.  Large  loose  webs  on  ends  of  branches  in  late  summer. 

Fall  Webworm,  p.  120 
Small  close  webs  on  twigs  of  poplar Poplar  Tent  Maker,  p.  146 

7.  Feeding  upon  broad-leaved  deciduous  trees   8 

Devouring  leaves  of  larch Larch  Sawfly,  p.  146 

S.    Larger,  hairy  caterpillars,  non-loopers  9 

Smaller,  smooth  caterpillars  which  loop  in  crawling, 

Cankerworms,  p.  120 
g.     Conspicuously  marked  with  black,  white,  or  yellow  tufts  of  hairs, 

Tussock  Moths,  p.  121 

Caterpillars   gray  or  brown,   Avith   two   rows   of   dorsal   tubercles ; 

first  five  pairs  blue,  remaining  six  pairs  red.. Gipsy  Moth,  p.  122 


142  CONNECTICUT  EXPERIMENT   STATION  BULLETIN   292 

B.  Tunneling  in  the  Wood  : 

10.  Larvae  white,   without  legs    il 

Larvae  white  with  dark  brown  spots,  with  legs, 

Leopard  Moth,  p.  120 

11.  Round-headed  larvae 12 

Flat-headed  larvae  in  white  birch Bronze  Birch  Borer,  p.  147 

12.  Tunneling  in  base  of  linden Linden  Borer,  p.  148 

Tunneling  anywhere  in  trunk  of  black   locust.  Locust  Borer,  p.  148 
Tunneling  in  trunk  and  branches  of  poplar  and  willow, 

Poplar  and  Willow  Borer,  p.  149 

C.  Sucking  Insects : 

13.  Green  or  white,  woolly  plant  lice,  visible  on  leaves  14 

Small  red  objects,  hardly  visible  on  leaves Mites,  p.  150 

14.  Green  plant  lice  on  leaves Green  Aphids,  p.  150 

White  woolly  plant  lice  on  beech  leaves. 

Beech  Woolly  Aphid,  p.  151 

15.  Scale  insects  fixed  on  bark  16 

Large  brown  plant  lice  on  bark  of  twigs   Willow  Aphids,  p.  151 

16.  Hemispherical  or  globular,  brownish  or  greenish  scale  insects  on 

twigs    17 

Pear-shaped,  white,  gray  or  brownish  scales   21 

17.  Scales   hemispherical    18 

Scales  globular,  on  oak  Oak  Gall  Scale,  p.  151 

18.  Scales  brown,  without  white  wax  secretion  ■ 19 

Scales  brown,  with  conspicuous  secretion  of  white  wax 20 

Scales  greenish-j^ellow,  in  pits  on  the  bark  of  English  oak. 

Pit-making  Oak  Scale,  p.  151 

19.  Scales  large  (6-8  mm.)  on  tulip  tree Tulip  Tree  Scale,  p.  152 

Scales  small   (2-6  mm.),  reddish-brown,  on  maple. 

Terrapin  Scale,  p.  152 

Larger   than   preceding,   often   clustered   on   many    different   kinds 

of  trees  and  shrubs European  Fruit  Lecanium,  p.  123 

20.  Chocolate   brown   with   white  wax   fringe   in   crevices   of  bark  on 

elm  European  Elm  Scale,  p.  153 

Medium  brown   on   twigs    of   maple;    white   ovisac    develops   and 
becomes  very  prominent  under  posterior  portion  of  body. 

Cottony  Maple  Scale,  p.  153 

21.  Gray  or  dirty  white  on  elm  twigs Elm  Scurfy  Scale,  p.  154 

Gray  or  brownish,  often  same  color  as  bark,  on  a  great  variety 

of  trees  and  shrubs Oyster-shell  Scale,  p.  123 


Larch  Case  Bearer  {Coleophora  laricella  Hubn.) 

The  young  larvae  of  the  larch  case  bearer  tunnel  out  the  outer 
half  of  each  needle,  and  when  it  is  completely  hollowed  out,  cut  it 
off  at  the  base  of  the  excavated  portion  and  use  the  latter  as  a  case, 
living  in  it  and  carrying  it  about  while  feeding.  They  spend  the 
winter  in  these  cases,  fastening  them  to  the  twigs  by  silken  threads. 
When  warm  weather  comes  in  the  spring,  the  larvae  dislodge  their 
cases  and  migrate  to  the  leaves,  upon  which  they  feed.  They  also 
cut  off  other  needles  to  enlarge  their  cases  and  continue  to  do 
this  until  May,  when  they  pupate  within  the  cases.     The  adults 


INSECT  PESTS  OF  NURSERY  STOCK  143 

emerge  the  latter  part  of  May  and  lay  their  eggs  upon  the  leaves 
during  the  early  part  of  June.  The  adult  is  a  small  moth  with  a 
wing  expanse  of  about  9  mm.  It  is  silvery  grayish-brown  in  color 
with  narrow  front  and  rear  wings  having  a  long  fringe. 

There  is  no  practical  method  of  controlling  this  insect  in  for- 
ests or  large  plantations,  but  on  shade  or  ornamental  trees  spray- 
ing is  effective.  If  the  trees  are  sprayed  with  lime-sulphur  at  the 
rate  of  one  part  to  seven  parts  of  water  before  the  new  leaves 
start  in  the  spring,  many  larvae  will  be  killed  in  their  hibernating 
quarters.  Spraying  with  arsenate  of  lead  seems  to  have  no  effect 
upon  this  insect. 

(Report  for  1923,  page  288). 


Locust  Leaf  Miner  (Chalepus  dorsalis  Thunb.) 

The  adult  of  this  insect  is  a  beetle  about  one-fourth  of  an  inch 
in  length,  with  head,  legs,  and  an  area  along  the  middle  of  the 
wing-covers,  black ;  the  thorax  and  remaining  portion  of  the  wing- 
covers  are  orange-red. 

The  eggs  are  laid  on  the  under  sides  of  the  leaves  in  May,  and 
the  larvae  are  miners  within  the  leaves,  and  pupate  there.  The 
beetles  emerge  from  the  mines  in  July  and  fly  about,  soon  laying 
eggs  for  the  second  brood,  which  reaches  maturity  in  the  fall. 
The  beetles  hibernate  under  the  dead  bark  of  trees,  cracks  and  crev- 
ices, and  under  rubbish.  Though  the  black  locust  is  the  preferred 
food  plant  and  is  therefore  the  most  severely  injured,  this  insect 
also  attacks  dogwood,  elm,  oak,  beech,  cherry,  and  several  other 
species  of  trees. 

Locust  trees  may  be  protected  from  this  insect  by  spraying  with 
lead  arsenate  to  which  a  little  molasses  has  been  added. 

(Ohio  Bulletin  332,  page  231), 


Imported  Birch  Leaf  Miner  (Fenusa  pumila  Klug) 

The  adult  of  this  insect  is  a  small  black  sawfly  which  has  some- 
how been  introduced  from  Europe.  First  noticed  in  Connecticut 
in  1923,  the  adults  were  reared  and  identified  in  1924,  and  the 
insect  has  now  spread  throughout  New  England  and  eastern  New 
York.  There  are  apparently  three  generations  each  year,  the  win- 
ter being  passed  as  pupae  in  the  ground.  The  larvae  make  blotch 
mines  on  the  tender  or  terminal  leaves,  as  are  shown  on  Plate 
VIII,  a,  especially  on  sprouts  or  low  trees  of  the  gray  birch,  the 
paper  birch,  and  the  European  white  birch.  Several  larvae  in  a  leaf 
unite  in  mining  the  entire  leaf.     No  remedy  is  known. 

(Report  for  1924,  page  340). 


144  CONNECTICUT  EXPERIMENT  STATION  BULLETIN   292 

Birch  Skeletonizer  (Bucculatrix  canadensisella  Chambers) 

This  is  a  native  American  insect  of  periodical  abundance,  and 
there  is  an  annual  generation  which  hibernates  in  ribbed  cocoons 
on  old  leaves  on  the  ground.  The  adult  moths  emerge  and  lay 
eggs  in  June  and  July.  The  eggs  hatch  in  15  days,  and  the  young 
larvae  for  the  first  three  instars  (on  the  average,  about  four 
weeks)  mine  in  the  leaves.  They  then  emerge  and  feed  upon  the 
under  side  of  the  leaves,  skeletonizing  them.  They  molt  in  white, 
circular  or  oval  flattened  cases  on  the  leaves.  The  chief  food  plants 
are  the  gray,  paper,  yellow,  and  European  white  birches.  The 
larvae  and  their  work  are  shown  on  Plate  VIII,  b. 

The  remedy  is  to  sprav  with  lead  arsenate. 

(Bulletin  288). 

Elm  Leaf  Beetle  {GaleruccUa  xanthomelaena  Schr.) 

The  work  of  the  elm  leaf  beetle  is  found  in  the  nurseries  of  the 
State  nearly  every  year.     Some  seasons  it  is   serious  and  must 


Fig.  25.    Larvae  and  work  of  the 
elm  leaf  beetle. 

interfere  with  the  growth  of  the  trees.  It  is  another  insect  of 
European  origin  but  has  been  in  this  country  for  nearly  ninety 
years,  and  is  distributed  generally  throughout  the  eastern  United 
States.  In  the  early  nineties  many  fine  old  elms  were  destroyed 
by  this  beetle  in  southern  New  England. 

The  beetles  live  over  the  winter  in  houses,  barns,  church  bel- 
fries and  out-buildings.  They  leave  their  winter  quarters  in  early 
spring,  mate,  and,  as  soon  as  the  leaves  unfold,  eat  small  round 
holes  in  them.  In  May  or  early  June,  the  females  lay  small  clus- 
ters of  yellowish  eggs  on  the  under  side  of  the  leaves.  Each 
female  may  lay  five  or  six  hundred  eggs.  In  about  a  week  the 
eggs  hatch  and  the  young  larvae  or  grubs  feed  on  the  under  side 
of  the  leaves,  as  shown  in  Fig.  25,  and  on  Plate  IX,  b,  become 


INSECT  PESTS  OF  NURSERY  STOCK  145 

full  grown  in  about  three  weeks,  and  crawl  down  the  trees  to 
pupate  on  the  ground.  The  pupa  stage  lasts  about  ten  days.  Then 
the  adult  beetles  emerge  and  lay  eggs  for  the  second  generation, 
which  seldom  does  much  damage  in  Connecticut,  and  go  early  into 
winter  quarters. 

There  is  no  reason  why  this  insect  should  be  a  serious  pest  in 
nurseries  because  it  is  easily  killed  by  an  application  of  arsenate 
of  lead  spray,  using  two  pounds  to  fifty  gallons  of  water.  The 
best  time  to  apply  this  is  soon  after  the  eggs  have  hatched,  which  is 
around  the  first  of  June. 

(Bulletin  155). 


Willow  Flea  Beetle  (Crepidodera  helxines  Linn.) 

This  is  a  small,  bright  green  or  occasionally  blue,  metallic,  jump- 
ing beetle,  with  rather  prominent  punctures  on  the  wing-covers, 
and  about  one-tenth  of  an  inch  in  length.  It  is  often  rather 
abundant  on  willows  in  nurseries,  and  the  beetles  eat  many  round 
holes  in  the  leaves.  It  lives  through  the  winter  in  the  adult  stage, 
but  its  life  history  is  not  well  known.  Spraying  the  foliage  with 
lead  arsenate  is  the  remedy. 

(Kentucky  Bulletin  120,  page  61). 

Imported  Willow  Leaf  Beetle  (Plagiodera  versicolora  Laich.) 

This  insect  has  recently  become  established  in  the  United  States 
in  the  vicinity  of  New  York  City.  It  was  first  found  in  Connecti- 
cut at  Greenwich  in  192 1.  At  that  time  the  beetles  and  larvae 
were  quite  numerous  and  were  defoliating  willows.  Since  then  the 
insect  has  spread  over  the  State  and  can  be  found  in  nearly  all 
nurseries  where  willows  are  grown.  The  beetles  appear  late  in 
April  or  early  May  and  feed  for  some  time ;  then  deposit  eggs. 
The  beetles  are  moderately  stout,  about  one-eighth  of  an  inch 
long,  and  of  a  dark,  metallic-blue  color.  When  the  eggs  hatch,  the 
young,  bluish-black  grubs  feed  on  the  under  side  of  the  leaves, 
often  skeletonizing  them.  This  insect  and  its  work  is  shown  on 
Plate  IX,  c. 

Spraying  with  lead  arsenate  is  effective. 

(Report  for  1921,  page  195). 

Cottonwood  Leaf  Beetle  {Lina  scripta  Fabr.),  Spotted  Wil- 
low Leaf  Beetle  {Lina  lapponica  Linn.) 

These  insects  are  well-known  pests  of  poplars  and  willows.  In 
Connecticut  most  of  the  injury  is  done  to  Lombardy  and  Carolina 
poplars.  Both  species  of  beetles  cause  injury,  but  Lina  scripta 
is  the  more  common  in  this  State. 


146  CONNECTICUT  EXPERIMENT  STATION  BULLETIN  292 

The  life  history,  habits,  and  the  control  measures  are  about  the 
same  for  both  species,  so  they  may  be  treated  together  in  this 
paper. 

The  beetles  appear  early  in  the  spring  when  leaf  growth  starts, 
and  begin  to  feed  on  the  foliage.  In  a  short  time  oviposition  takes 
place,  and  the  reddish-yellow  eggs  are  laid  in  clusters  on  the  under 
side  of  the  leaves.  From  these  hatch  small  black  grubs  which 
skeletonize  the  under  surface  of  the  leaves.  As  they  grow  larger 
they  eat  out  ragged  holes  in  the  leaves  and  often  leave  only  the 
midribs.  When  full  grown  they  pupate  on  the  leaves  and  soon 
the  adults  emerge.    There  are  three  broods  in  a  season. 

Spraying  with  arsenate  of  lead,  using  three  pounds  to  a  hundred 
gallons  of  water,  will  control  this  pest.  An  effort  should  be  made 
to  spray  the  under  side  of  the  leaves,  as  the  young  grubs  feed  only 
on  the  lower  surface  until  they  are  about  half  grown.  The  smooth 
surface  of  the  poplar  and  willow  leaves  causes  the  spray  to  roll 
off  or  collect  in  drops,  but  this  may  be  overcome  by  adding  a 
spreader  like  calcium  caseinate,  mixing  one  pound  with  a  hun- 
dred gallons  of  the  spray  mixture. 

(Ohio  Bulletin  332,  pages  259,  261). 

Fall  Webworm.     See  page  120 

Poplar  Tent-Maker   {Melalopha  inchisa  Hubn.) 

The  caterpillars  feed  gregariously  upon  the  foliage  of  various 
kinds  of  poplars  and  willows  and  make  small  nests  upon  the  twigs 
which  resemble  those  of  the  brown-tail  moth.  Unlike  them,  how- 
ever, the  caterpillars  do  not  remain  in  the  webs  through  the  win- 
ter. 

There  are  probably  two  generations  each  year,  as  the  moths  are 
present  in  March,  April,  and  May,  and  again  in  July  and  August. 
The  full-grown  caterpillar  is  about  an  inch  and  a  half  long,  dark 
brown,  with  narrow  yellow  stripes  extending  lengthwise.  The 
head  and  legs  are  black,  the  under  surface  of  the  body  honey- 
yellow.  The  fourth  and  eleventh  segments  each  bear  a  closely 
set  pair  of  high,  pointed  tubercles  dark  brown  in  color  and  some- 
what hairy. 

Spraying  with  lead  arsenate  is  the  remedy. 

(Report  for  1911,  page  310). 

Larch  Sawfly  (Lygaeonemafus  erichsoni  Hart.) 

The  larch  sawfly  was  first  noticed  in  this  country  in  J\'Iassachu- 
setts  in  1881.  Since  that  time  it  has  caused  considerable  injury  to 
larch  plantations.     In  Connecticut  it  has  been  reported  from  the 


INSECT  PESTS  OF  NURSERY  STOCK 


147 


northern  parts  of  the  State  where  larch  grows  naturally.  Both 
the  adults  and  the  larvae  injure  trees,  the  adults  injuring  the  ter- 
minal twigs  by  inserting  eggs,  and  the  larvae  eating  the  leaves.  The 
adult  female  selects  the  young,  green,  terminal  shoot  in  which  to 
deposit  eggs,  causing  it  to  die  or  severely  injuring  and  distorting 
it.  The  eggs  are  laid  in  May  and  hatch  in  about  ten  days.  The 
young  larvae  feed  on  the  leaves  and  are  full  grown  in  three  or 
four  weeks.  They  then  make  cocoons  under  rubbish  on  the  ground, 
where  they  spend  the  winter.  The  adults  emerge  the  following 
spring.    Larvae  and  cocoons  are  shown  on  Plate  IX,  a. 

On  small  trees  in  nurseries,  injury  may  be  prevented  by  spray- 
ing with  three  pounds  of  arsenate  of  lead  in  fifty  gallons  of 
water.  In  woodlands  the  insect  is  hard  to  control  because  of 
the  size  of  the  trees  and  the  difficulty  in  spraying.  In  Connecti- 
cut the  best  time  to  spray  is  early  in  June  soon  after  the  eggs 
have  hatched. 

(Report  for  1915,  page  125). 


Fig.  26.     Worl:  of  the  bronze  birch  liorcr. 


Canker  WORMS.     See  page   120 
Tussock  Moths.    See  page  121 


Leopard  Moth.     See  page  120 

Bronze  Birch  Borer   {AgrUns  anxius  Gory) 

Many  cut-leaf  white  birches  in  Connecticut  have  died  during 
the  past  few  years  as  a  result  of  the  attack  of  the  bronze  birch 
borer.  The  European  white  birch,  Betiila  alba,  is  the  species  chief- 
ly injured.  Our  native  birches  are  seldom,  though  occasionally 
attacked  bv  the  insect. 


148  CONNECTICUT  EXPERIMENT   STATION  BULLETIN   292 

Thinning  of  the  foHage  in  the  top  of  the  tree  is  an  indication 
of  the  presence  of  the  borer.  Later,  the  top  branches  die,  and  the 
following  season  the  process  continues  until  the  tree  is  killed.  A 
careful  examination  shows  ridges  or  swellings  on  the  branches  one- 
half  to  one  inch  in  diameter  before  anything  is  wrong  with  the 
foliage.  Where  the  beetles  have  emerged  there  may  be  semi- 
circular exit  holes.    Injured  wood  is  shown  in  Fig.  26. 

There  is  one  annual  generation  each  year.  The  larvae  live 
through  the  winter  in  cells  just  under  the  bark  and  pupate  early 
in  May.  The  beetles  emerge  late  in  May  or  early  in  June  and  lay 
eggs  in  the  crevices  of  the  bark.  The  small  larvae  hatching  from 
the  eggs  tunnel  first  near  the  bark  and,  as  they  grow  larger,  into 
the  wood. 

Infested  trees  should  be  cut  and  burned  before  June  i  to  pre- 
vent the  flight  of  the  beetles  from  infested  trees  to  healthy  ones. 
As  the  adults  feed  to  some  extent  upon  the  foliage,  spraying  with 
lead  arsenate  early  in  June  is  recommended. 

(Report  for  1922,  page  359). 

Linden  Borer  (Saperda  vestita  Say) 

This  insect  often  causes  serious  injury  to  young  linden  trees. 
In  nurseries  many  have  been  injured  at  the  base  so  that  they 
break  in  wind-storms.     See  Plate  X,  b. 

The  adult  beetle  is  black,  covered  by  a  dense  olive  pubescence, 
and  usually  has  three  black  spots  on  each  wing-cover,  though 
these  are  sometimes  absent.  The  beetles  appear  during  the  sum- 
mer and  after  feeding  on  the  green  bark  of  growing  shoots,  leaf 
stems,  and  on  the  under  side  of  leaves,  they  begin  to  lay  their 
eggs.  The  females  with  their  jaws  make  slight  incisions  in  the 
bark  where  they  lay  their  eggs.  The  grubs  on  hatching  mine 
under  the  bark  and  into  the  wood.  The  injury  takes  place  at  or 
near  the  ground — never  more  than  a  foot  from  it — and  some- 
times in  the  larger  roots. 

The  only  remedy  is  to  kill  the  borers.  This  may  be  done  with 
a  pointed  knife  or  a  wire.  The  borer  may  be  extracted  by  means 
of  a  small  wire  with  a  barbed  point  like  a  harpoon. 

(Report  for  1915,  page  186). 

Locust  Borer   (Cyllens  robiniae  Forst.) 

The  adult  is  one  of  the  long-horned  beetles  about  three- fourths 
of  an  inch  long,  black  in  color,  with  bright  yellow  bands  extend- 
ing across  the  body.  The  insect  is  very  destructive  to  our  com- 
mon locust,  Rohinia  pseudoacacia,  and  also  to  the  rose  acacia, 
Rohinia  hispida.  The  beetles  appear  in  September,  when  they 
may  be  found  feeding  on  the  blossoms  of  goldenrod.     Eggs  are 


INSECT  PESTS  OF  NURSERY  STOCK  149 

laid  about  that  time  in  clusters  or  singly,  on  the  roughened  bark 
of  trunks  and  branches.  The  young  larvae  hatching  from  them 
tunnel  into  the  bark,  where  they  spend  the  winter.  In  spring 
they  resume  feeding  and  go  into  the  heart-wood.  An  enlarge- 
ment forms  at  the  entrance  of  the  burrow,  and  in  time  the  trunks 
of  young  trees  become  much  deformed ;  on  older  trees  the  branch- 
es are  injured. 

Successful  and  practical  measures  for  the  control  of  this  insect 
have  never  been  found.  If  only  a  few  trees  are  involved,  the 
larvae  may  be  dug  from  their  burrows.  Repellent  washes  applied 
to  the  trunks  of  trees  during  the  egg-laying  period  have  proven 
expensive  and  only  moderately  effective. 

(Ohio  Bulletin  332,  page  316). 

Poplar  and  Willow  Borer  (Cryptorhynchus  lapathi  Linn.) 

This  insect  is  one  of  the  snout  beetles  or  weevils  and  is  about 
one-third  of  an  inch  long,  dark  gray  in  color,  except  the  tips  of 
the  wing-covers,   which  are   paler.      (See   Fig.   27).     Injury   is 


Fig.  27.   Poplar  and  willow  borer, 
twice  enlarged. 

caused  by  both  adults  and  larvae.  The  adult  punctures  the  bark 
of  the  trees  and  the  grubs  bore  into  the  trunk  and  branches.  The 
injury,  shown  on  Plate  X,  a,  is  greatest  to  nursery  stock  and  newly 
set  trees ;  after  the  trees  are  older  and  well  established,  less  in- 
jury occurs. 

The  winter  is  passed  in  the  larval  stage  within  the  host  plant. 
The  adults  appear  late  in  July  and  are  most  abundant  in  August. 
Mating  and  egg-laying  take  place  about  ten  days  after  emergence. 

Infestation  is  indicated  by  dead  patches  of  bark,  dead  or  dying 
trees  or  limbs  with  irregular  swellings  or  galls  formed  over  tun- 
nels. 

One  remedy  is  to  cut  out  and  burn  all  infested  wood  before 
May  or  June,  to  prevent  the  grubs  from  reaching  maturity.  Prob- 
ably the  insect  can  be  controlled  by  thoroughly  coating  the  bark  in 
July  with  arsenate  of  lead.  Painting  the  trunks  of  trees  early 
in  April  with  Carbolineum  or  some  other  repellent  has  also  been 
recommended. 

(Ohio  Bulletin  332,  page  319). 


150  conni-xticut  experiment  station  lulletin  292 

Sucking  Insects 

Mites 

Though  "mites"  or  "red  spider"  are  not  insects,  there  are  sev- 
eral species  which  injure  the  leaves  of  trees,  causing  them  to  turn 
dull  and  brown  the  latter  part  of  the  season.  Mites  belong  to 
the  Order  Acarina  (Class  Arachnida)  and  usually  have  four 
pairs  of  legs,  thus  differing  from  insects  (Class  Insecta)  which 
usually  have  three  pairs  of  legs  in  the  adult  stage. 

In  mite  infestations  pale,  brownish  spots  are  noticed  on  the 
leaves,  which  may  later  cover  the  entire  foliage.  When  these  spots 
are  examined  with  a  magnifying  glass,  tiny  globular  eggs,  egg- 
shells, mites,  and  their  cast  skins  may  be  seen. 

One  of  the  common  mites  in  nurseries,  especially  on  oak  and 
maple,  is  Paratefranychus  bicolor  Banks.  The  European  red 
mite,  Paratetranychus  pilosus  C.  &  F,  (see  page  140),  which  is  an 
important  pest  6f  fruit  trees,  also  occurs  on  elm  and  probably  on 
other  kinds  of  shade  trees.  The  common  "red  spider"  of  green- 
houses, Tctranychus  bimaculatus  Harvey  (telarius  Linn.)  may 
injure  the  foliage  of  almost  any  tree  species.  With  T.  bimaculatus, 
evidently  the  adults  hibernate,  but  with  P.  bicolor  and  P.  pilosus, 
reddish  or  brownish  eggs  are  laid  in  the  fall  on  the  bark  of  the 
trunk  and  branches.  On  hatching  in  spring,  the  young  mites 
find  their  way  to  the  leaves. 

The  remedies  are:  a  dormant  spray  of  a  miscible  oil  (i  -  15)  to 
kill  the  overwintering  eggs ;  a  summer  spray  of  linseed  oil  emul- 
sion to  kill  the  mites.    This  emulsion  may  be  made  as  follows : 

I  gallon  raw  linseed  oil 
1.5  pounds  soap  flakes 
I  gallon  water 
Dissolve  the  flakes  in  the  water,  stir  in  the  linseed  oil,  and  di- 
lute to  make  100  gallons. 
(Bulletin  252). 

Green  Aphids 

There  are  many  species  of  green  aphids  attacking  deciduous 
trees  during  the  growing  season.  In  fact,  nearly  every  tree  species 
has  one  or  more  species  of  aphids  infesting  its  leaves.  The 
aphids  may  occur  in  the  winged  or  wingless  forms.  They  suck 
the  sap  through  their  long  pointed  beaks  and  excrete  a  sticky  sub- 
stance called  "honey  dew,"  which  drips  upon  the  foliage,  giving 
the  leaves  a  varnished  appearance.  In  the  honey  dew  a  black 
fungus  or  sooty  mold  grows,  giving  the  leaves  a  blackened  appear- 
ance.   Ants  feed  upon  the  honey  dew  and  are  usually  present  on 


INSECT  PESTS  OF  NURSERY  STOCK  I5I 

aphid-infested  trees,  but  the  ants  do  no  harm  to  the  trees.  The 
presence  of  aphids  may  be  noticed  also  in  some  cases  by  the  curled 
leaves  or  the  abnormal  dropping  of  the  leaves. 

Aphids  may  be  killed  by  spraying  with  a  contact  spray  like  nico- 
tine solution  and  soap,  but  they  must  be  hit  by  it.  As  they  are 
mostly  on  the  under  leaf  surface,  the  spray  should  be  directed 
there.  Applications  should  also  be  made  before  the  aphids  are  de- 
structively abundant  and  before  the  leaves  are  curled  or  seriously 
injured. 


Beech  Woolly  Aphid   (PJiyllapJiis  fagi  Linn.) 

Trees  of  the  European  beech,  Fagus  sylvatica,  especially  the  pur- 
ple-leaved form,  are  usually  infested  in  Connecticut  by  a  white 
woolly  aphid  which  appears  on  the  under  side  of  the  leaves  in 
early  summer.  The  woolly  appearance  is  due  to  slender  wax  fila- 
ments secreted  by  the  aphids. 

They  may  be  controlled  like  other  aphids  with  a  spray  of  nico- 
tine solution  and  soap. 


Willow  Aphids 

Large  reddish  brown  aphids  are  often  present  in  large  num- 
bers on  the  twigs  of  willows,  where  they  lay  eggs  late  in  the  sea- 
son. These  belong  to  the  genus  Chaiiophorus,  two  species — vim- 
inalis  Monell  and  nigrae  Oest. — occurring  in  Connecticut.  There 
is  also  an  even  larger  species,  Longistigma  caryae  Harris,  which 
occurs  on  oak,  hickory,  maple,  elm,  poplar,  linden,  and  sycamore. 
The  remedy  is  that  given  above. 


Oak  Gall  Scale  (Kermes  sps.) 

Hard,  globular  scales  occur  on  oak  trees  in  nurseries  and  are 
usually  gray  or  brown  in  color.  There  are  several  species,  some 
smooth  and  shiny,  some  dull,  and  some  pubescent.  The  partially 
grown  females  winter  in  the  crevices  of  the  bark,  and  some  spe- 
cies in  the  spring  go  to  the  leaves.  The  young  appear  in  Juh' 
or  August.  The  bodies  of  the  females  often  remain  on  the  twigs 
for  nearly  a  year  after  they  die.     Shown  on  Plate  XV,  e. 

Spraying  the  dormant  trees  in  early  spring  with  a  miscible  oil 
(i  -  15)  is  effectu-e. 

Pit-Making  Oak  Scale  (Asterolccanium  variolosiim  Ratz.) 

This  scale  infests  several  species  of  oak  but  is  most  frequently 
encountered  on  English  or  golden  oak,  Ouercus  robur.     It  has  a 


152  CONNECTICUT  EXPERIMENT  STATION  BULLETIN  292 

smooth,  glassy,  convex  shell  about  one-sixteenth  of  an  inch  in 
diameter  and  is  of  a  beautiful  greenish-golden  color.  A  little  pit 
is  formed  around  each  insect,  from  whence  its  common  name 
arises.  It  is  also  called  the  golden  oak  scale.  It  is  believed  to  be 
single-brooded,  but  this  point  has  not  been  determined  for  Con- 
necticut. The  insect  passes  the  winter  in  the  egg-stage  under 
the  old  shells,  and  the  young  appear  in  May  and  June.  The  in- 
sect is  shown  on  Plate  XI,  c. 

A  dormant  spray  of  a  miscible  oil  (i  -  15)  is  probably  the  best 
means  of  control. 

(Ohio  Bulletin  332,  page  306). 

Tulip  Tree  Scale  {Tourney ella  liriodendri  Gmel.) 

This  is  our  largest  soft  scale,  the  females  being  brown,  hemi- 
spherical, and  nearly  one-third  of  an  inch  in  diameter,  shown  in 


I       Fig.  28.    Tulip  tree  scale. 

Fig.  28,  and  on  Plate  XI,  d.  The  males  are  oval,  gray,  and  flat- 
tened, and  about  an  eighth  of  an  inch  in  length.  The  scales  usu- 
ally occur  on  the  lower  branches  of  the  tulip  tree,  and  there  is  a 
single  generation  each  year,  the  young  appearing  in  September. 
The  remedy  is  to  spray  as  soon  as  the  leaves  fall,  using  a  miscible 
oil  or  a  nicotine  solution. 

(Report  for  1921,  page  176). 

Terrapin  Scale  (Lecanium  nigrofasciafum  Pergande) 

This  is  a  small,  oval,  and  very  convex  soft  scale,  reddish-brown 
in  color,  which  infests  the  small  twigs  of  maple  trees  (see  Plate 
XI,  b),  especially  the  red  and  silver  maples.  On  large  trees  it  is 
more  apt  to  be  on  the  lower  branches,  and  though  not  particularly 
a  nursery  pest,  it  is  occasionally  found  on  the  nursery  trees  of 
larger  size.  The  eggs  are  formed  under  the  old  shells  in  June  and 
hatch  late  in  June  or  early  in  July.    Only  the  females  live  through 


INSECT  PESTS  OF  NURSERY  STOCK  153 

the  winter,  and  they  are  in  a  partially  grown  state.  The  scales 
suck  the  sap  from  the  twigs  in  fall  and  spring,  becoming  mature 
about  June  i. 

The  remedies  are  contact  insecticides,  especially  miscible  oils 
( I  -  15),  applied  when  the  trees  are  donnant. 

(Report  for  1921,  page  183). 

European  Fruit  Lecanium.    See  page  123 

European  Elm  Scale  (Gossyparia  spuria  Mod.) 

This  is  a  chocolate-brown  scale,  oval  in  shape,  with  a  fringe  of 
white  wax  around  the  margin,  shown  on  Plate  XI,  a.  It  usually 
occurs  in  the  crevices  of  the  bark  of  trunk  and  larger  branches. 
There  is  one  generation  each  year,  the  insect  hibernating  on  the 
bark  in  a  partially  grown  state.  The  young  appear  in  June.  The 
standard  contact  sprays  will  kill  this  scale  at  almost  any  time  of 
the  year,  though  more  thorough  applications  can  be  made  when 
the  trees  are  dormant. 

(Report  for  1905,  page  235). 


Cottony  Maple  Scale  (Ptdvinaria  vitis  Linn.) 

This  insect  is  perhaps  the  most  conspicuous  of  all  the  scale 
insects  on  account  of  the  abundant  secretion  of  wax  surround- 
ing the  eggs.  During  the  winter  it  occurs  on  the  bark  and  resem- 
bles any  other  large,  brown,  soft  scale,  but  about  the  time  the  trees 
begin  to  grow,  the  posterior  end  of  the  insect  becomes  raised,  and 
the  egg-sac  begins  to  protrude,  as  shown  on  Plate  XI,  e.  When 
fully  developed  it  is  as  long  as  the  insect  itself  and  resembles  a 
tuft  of  cotton.  Each  female  deposits  about  three  thousand  eggs, 
which  hatch  in  late  June  or  early  July.  The  young  at  first  go  to 
the  leaves  and  establish  themselves  mostly  on  the  under  side  along 
the  midrib  and  veins.  Before  the  foliage  drops,  they  return  to 
the  twigs  and  settle  on  the  bark  for  the  winter. 

In  Connecticut  this  insect  has  occurred  abundantly  only  in 
the  vicinity  of  Stamford  and  attacks  silver  and  red  maples,  though 
all  other  kinds  are  also  infested  in  some  portions  of  the  Middle 
West,  where  there  are  periodical  outbreaks  every  eight  or  ten 
years.  It  occurs  in  Connecticut  nurseries  on  a  variety  of  trees, 
shrubs,  and  vines,  but  is  seldom  sufficiently  abundant  to  cause 
injury.     It  is  perhaps  the  most  common  on  maple. 

The  remedy  is  to  spray  the  dormant  trees  in  early  spring,  using 
one  of  the  miscible  oils  (i  -  15). 

(Report  for  1921,  page  179). 


154  CONNECTICUT  EXPIiiaMliNT   STATION  BULLETIN   292 

Elm  Scurfy  Scale  (Chionaspis  avwricana  Johnson) 

This  scale,  which  occurs  on  the  twigs  and  branches  of  ehn.  is 
dirty-white  or  gray  in  color  and  somewhat  resembles  the  oyster- 
shell  scale.  It  passes  the  winter  in  the  form  of  purplish  eggs  under 
the  old  shells,  and  there  are  two  generations  each  season.  Small 
branches  are  killed  in  severe  infestations,  and  the  general  vitality 
of  the  tree  is  lowered. 

Spraying  the  dormant  trees  with  liquid  lime-sulphur  (i  -8)  or 
with  one  of  the  miscible  oils   (i  -  15)  will  control  this  insect. 

(Ohio  Bulletin  332,  page  290). 

Oyster-Shell  Scale.     See  page  123 


INSECTS  INJURING  SHRUBS  AND  VINES 
Key 

A.  Feeding  upon  the  leaves  : 

1.  Conspicuous  caterpillars,  bearing  horns  or  spines    2 

Conspicuous  caterpillars,  without  distinct  horns  or  spines 4 

2.  Caterpillars  with  horns   or  fleshy  protuberances 3 

Caterpillars  2-3  inches  long,  covered  with  branched  stinging  spines, 

pale  green  with  reddish  band  along  each  side, 

lo  Caterpillar,  p.  155 
Caterpillars  one  inch  long  or  less,  each  end  with  a  pair  of  promi- 
nent tubercles  bearing  stinging  spines ;   color  brown  with  green 
saddle Saddle-back  Caterpillar,  p.   155 

3.  Green  caterpillars  with  single  horn  on  tail,  on  grape  or  Virginia 

creeper Sphinx  Caterpillars  or  Horn  Worms,  p.  156 

Brown  caterpillars  with  fleshy  protuberances  on  each  side  of  tho- 
racic segments,  on  Dutchman's  pipe  vine, 

Pipe-Vine  Caterpillar,  p.  156 

4.  Large  fleshy  caterpillars.  3-4  inches  long,  bluish-green,  with  promi- 

nent tubercles,  usually  feeding  on  rosaceous  plants, 

Cecropia  Caterpillar,  p.  156 
Smaller    (1-2   inches),   finely   cross-striped   with  black,  white   and 
orange,  feeding  upon   Virginia  creeper. 

Eight-spotted  Forester,  p.  157 

5.  Small,  green,  slug-like  caterpillars  on  rose.... Rose  Sawflies,  p.  157 
Larger,  gray,  slug-like  caterpillars  on  Lonicera, 

Honeysuckle  Sawflies,  p.  158 

B.  Borers  in  stems  : 

6.  White  grub,  about  one  inch  long,  tunneling  in  lilac  or  privet, 

Lilac  Borer,  p.  158 

Very    small,    flat-headed    white   grub,    forming   swellings    on   rose 

stems Rose  Stem  Girdler,  p.  158 

C.  Forming  galls  on  leaves  : 

7.  Shiny,  semi-transparent  galls  on  leaves  and  tendrils  of  grape, 

Grape-vine  Tomato  Gall,  p.  158 
Small  pocket  galls  on  leaves Eriophyid  Mites,  p.  159 


INSECT  PF.STS  OF  NURSERY  STOCK  155 

D.     Sucking  sap   from  leaves  or  bark  : 

8.  Scale  insects  protected  by  shells,  mostly  on  bark 9 

Green  plant  lice  on  leaves Aphids,  p.  150 

9.  Female  scale,  circular  or  nearly  so    10 

Female   scale,  pear-shaped,   dark  gray,   on   Euonymus, 

Euonymus  Scale,  p.  159 
10.     Female   scales,   2-3   mm.,   snow-white,   exuviae   marginal,   light  yel- 
low, eggs  purple,  on  rose  and  blackberry Rose  Scale,  p.  iS9 

Same   size,   scale   whitish  but  more  or  less   covered  with  bark  of 
host,    exuviae   marginal,   orange-yellow ;    on    cherry,    privet,    and 

Catalpa  bungei White  Peach  Scale,  p.  159 

Female  scales  less  than  2  mm.,  dark  gray,  exuviae  central,  yellow, 

San  Jose  Scale,  p.  137 

lo  Caterpillar  {Antomcris  io  Fabr.) 

This  caterpillar  is  from  two  to  three  inches  long  when  fully 
grown,  pale  green,  with  a  reddish  and  white  stripe  along  each  side, 
each  segment  bearing  a  number  of  tubercles  arranged  crosswise 
in  a  row,  as  shown  on  Plate  XII,  c.  Each  tubercle  has  a  number 
of  spreading,  stinging  spines  which  cause  an  intense  itching  or  rash 
on  coming  in  contact  with  the  human  skin.  Apparently  there  is 
only  one  generation  each  year,  and  the  insect  passes  the  winter  in 
its  cocoon  among  the  leaves  on  the  ground.  The  moths  emerge 
in  June  and  July.  The  female  has  a  wing-spread  of  about  three 
inches,  and  the  male  about  two  and  one-half  inches.  The  ground 
color  is  yellow  with  reddish  markings,  and  in  the  female  the  entire 
fore  wings  are  tawny.  On  each  rear  wing  in  both  sexes  there 
is  a  bluish  eye  spot  margined  with  black,  and  with  a  white  dash 
in  the  center ;  between  the  spot  and  the  wing-margin  are  two  con- 
centric rings,  one  red  and  the  other  black. 

The  caterpillar  feeds  upon  many  kinds  of  shrubs  and  trees. 
Spraying  with  lead  arsenate  is  the  remedy. 

(Ohio  Bulletin  332,  page  270). 

Saddle-Back  Caterpillar  {Sihine  sfiniulea  S.  &  A.) 

The  caterpillars  of  this  species  are  often  gregarious  and  feed 
upon  a  large  number  of  plants.  They  are  nearly  an  inch  long, 
without  true  legs,  and  are  brown  and  green  in  color.  Both  ends  of 
the  body  and  the  long  tubercles  are  brown,  but  the  middle  of  the 
body  looks  as  though  covered  by  a  bright  green  blanket  with 
an  oval  opening  on  the  back,  as  shown  on  Plate  XII,  a.  This  gives 
it  the  common  name  "saddle-back."  On  the  prominent  brown 
tubercles,  and  laterally  on  the  smaller  green  ones,  there  are 
branched,  stinging  spines  which  to  the  touch  are  quite  painful  for 
an  hour  or  two.  The  reddish-brown  moth  has  a  wing-spread  of 
about  one  and  one-half  inches.     There  is  one  generation  annually. 

Spraying  with  lead  arsenate  will  prevent  defoliation. 

(Report  for  1914,  page  188). 


156  connecticut  experiment  station  bulletin  292 

Sphinx  Caterpillars  or  Horn  Worms 

Grape  vines,  Virginia  creeper,  and  Boston  ivy  are  often  eaten 
by  caterpillars  of  this  group.  Most  of  them  may  be  distinguished 
by  the  sharp  horn  on  the  back  near  the  tail,  as  shown  in  Fig.  29, 
and  several  species  belonging  to  different  genera  may  be  encoun- 
tered.   All  belong  to  the  family  Sphingidae. 

The  abbot  sphinx,  Sphecodina  abbolti  Swains.,  has  in  place  of 
the  horn  a  shiny  spot  or  tubercle.    This  caterpillar  is  brown,  veined 


Fig.  29.    A  sphinx  caterpillar  or 
horn  worm. 

with  a  darker  brown,  but  a  form  occurs  having  a  large  green  patch 
on  the  dorsal  portion  of  each  segment. 

All  sphinx  moths  have  large  bodies  and  long  narrow  wings.  They 
fly  at  dusk,  poise  with  vibrating  wings  before  deep-throated  flow- 
ers, and  for  this  reason  are  called  "humming-bird  moths." 

Hand  picking  is  the  usual  remedy,  but  if  the  caterpillars  are  in- 
juriously abundant  in  nursery  or  vineyard,  spraying  with  lead  ar- 
senate will  prevent  defoliation  of  the  vines. 

Pipe- Vine  Caterpillar  {Papilio  philenor  Linn.) 

Wherever  the  Dutchman's  pipe,  Aristolochia  sipho,  is  grown,  the 
leaves  may  be  eaten  by  the  pipe-vine  caterpillar.  This  caterpillar 
is  velvety  dark  brown  or  black,  marked  with  orange  spots  and 
bearing  a  number  of  long  black  and  orange  protuberances,  and  is 
shown  with  cocoon  on  Plate  XII,  d.  When  fully  grown  it  is  two 
inches  or  more  in  length.  The  adult  is  a  swallow-tail  butterfly 
having  a  wing-spread  of  3-3.5  inches,  velvety  black  with  metallic 
bluish  or  greenish  reflections.  There  are  two  generations  each 
year. 

Spraying  the  vines  with  lead  arsenate  is  probably  the  best  rem- 
edy. 

(Holland's  Butterfly  Book,  page  315). 

Cecropia  Caterpillar  (Samia  cecropia  Linn.) 

This  is  one  of  the  largest  caterpillars  commonly  found  feeding 
upon  nursery  stock  and  is  from  3-4  inches  long  when  full  grown 


INSECT  PESTS  OF  NURSERY  STOCK  157 

and  about  three-fourths  of  an  inch  thick.  It  has  a  pecuhar  bluish- 
green  color  with  a  cross  row  of  tubercles  on  each  segment;  those 
on  the  second,  third  and  fourth  segments  are  red,  the  other  dorsal 
ones  yellow,  with  pale  blue  tubercles  along  the  sides  near  the 
breathing  pores.  (Shown  on  Plate  XII,  e).  The  cocoon  is  brown 
and  fastened  lengthwise  to  a  twig.  The  moth  has  a  wing-spread, 
of  4-6  inches,  is  gray  and  prettily  marked  with  black,  red,  and 
creamy-white,  with  a  lunule  on  each  wing.  There  is  only  one 
generation  each  year,  and  it  passes  the  winter  in  the  cocoon. 

The  caterpillar  feeds  upon  spiraea  and  other  plants  of  the  rose 
family,  but  is  also  found  upon  box-elder  and  willow. 

Hand-picking  is  perhaps  the  only  remedy  needed  in  Connecticut, 
but  where  abundant,  the  caterpillars  may  be  controlled  by  spray- 
ing with  lead  arsenate. 

(Ohio  Bulletin  332,  page  266). 


Eight-Spotted  Forester  {Alypia  octomaculata  Fabr.) 

The  caterpillars  of  this  insect  occasionally  defoliate  Virginia 
creeper  and  also  feed  upon  grape,  barberry,  and  rose.  They  feed 
in  July,  and  are  between  one  and  two  inches  in  length.  Their 
general  color  is  brown  with  a  bluish  tinge.  Each  segment  is  nar- 
rowly banded  crosswise  with  black  and  white,  with  a  broader  band 
of  orange  dotted  with  small  black  dots.  Head  and  cervical  shield 
are  orange  with  black  dots.  The  moth  is  black  with  two  round 
yellow  spots  on  each  fore  wing  and  two  smaller  white  spots  on  each 
rear  wing.  The  insect  passes  the  winter  in  the  chrysalid  stage  in 
the  soil,  and  there  is  only  one  annual  generation.  Caterpillars 
and  moths  are  shown  on  Plate  XII,  b. 

Hand-picking  and  spraying  with  lead  arsenate  are  the  remedies. 

(Report  for  1916,  page  118). 


Rose  Sawflies  {Caliroa  aethiops  Fabr.  and  others) 

Small,  greenish  slugs  often  feed  upon  rose  leaves,  skeletonizing 
them.  Several  species  may  be  involved,  one  of  the  most  common 
being  named  above.  This  has  only  one  annual  generation,  but 
some  of  the  other  species  probably  have  more.  The  adults  are 
four-winged  flies,  and  on  account  of  the  toothed  ovipositor  in  the 
female  they  are  called  sawflies. 

The  larvae  or  slugs  are  easily  killed  by  spraying  with  lead  ar- 
senate, with  nicotine  solution  and  soap,  or  fresh  hellebore  applied 
as  a  spray  or  dust. 

(U.  S.  Farmers'  Bulletin  1252). 


158  CONNECTICUT  EXPERIMENr   STATION  BULLETIN   292 

Honeysuckle  Sawflies  (Abia  americana  Cress.,  and 
A.  inflata  Nort.) 

The  leaves  of  various  species  of  bush  and  dimbing  honeysuckles 
are  sometimes  eaten  by  the  larvae  of  at  least  the  two  species  of 
sawflies  named  above.  In  one  case  the  climbing  honeysuckle  on  a 
wire  fence  was  defoliated.  The  larvae  were  grayish-green  with 
orange  spots,  and  presumably  there  is  only  one  generation  each 
year. 

Defoliation  may  be  prevented  by  spraying  with  lead  arsenate. 

'•  Lilac  Borer  (Podosesia  syringae  Harris) 

Lilac  and  privet  are  often  injured  by  white  grubs  burrowing  in 
the  stems.  Sometimes  the  stems  break  over,  and  in  other  cases 
they  remain  standing  and  present  an  unthrifty  appearance.  The 
adult  is  a  wasp-like,  clear-wing  moth  of  the  family  Sesiidae,  and 
there  is  one  generation  each  year.     (See  Plate  XIH,  a). 

The  best  means  of  control  is  to  cut  out  and  burn  the  infested 
stems. 

(Report  for  1905,  page  260). 

Rose  Stem  Girdler  (Agrilus  viridus  var.  fagi  Ratz.) 

Recently  an  European  insect  has  appeared  in  Connecticut,  called 
the  rose  stem  girdler,  which  causes  the  formation  of  swellings  on 
the  stems  of  various  species  and  varieties  of  rose,  as  shown  on 
Plate  XHI,  b.  Rosa  rugosa  and  R.  hugonis  have  been  noticed  with- 
these  swellings,  which  are  the  result  of  the  plant  making  an  at- 
tempt to  heal  the  wounds  around  the  galleries  of  the  larvae. 

The  adult  is  a  metalHc,  coppery  beetle,  about  one-third  of  an 
inch  long,  which  lays  eggs  singly  on  the  bark  in  June  and  July. 
The  larva  is  a  slender  white,  flat-headed  grub. 

The  only  known  remedy  is  to  cut  and  burn  the  infested  stems  in 
winter  or  early  spring  before  the  beetles  emerge. 

(Report  for  1925,  page  325). 

Grape-vine  Tomato  Gall   (Lasioptera  vitis  O.S.) 

The  leaves,  peduncles,  tendrils,  and  tender  shoots  of  grape 
vines  are  often  marked  and  seriously  distorted  by  irregular  water 
thickenings  or  swellings  which  are  sometimes  red  and  sometimes 
green,  as  shown  on  Plate  XV,  b.  The  adult  is  a  two-winged  fly~ 
which  places  its  eggs  on  or  in  the  succulent  tissues.  The  larvae 
develop  in  cells  in  the  center  of  the  galls. 

The  only  known  method  of  control  is  to  clip  off  and  burn  the 
infested  tips. 

(Report  for  19 16,  page  146). 


INSECT  PESTS  OF  XURSERY  STOCK  I  59 

Eriophyid  Mites   (Family  Eriophyidae) 

The  leaves  of  shrubs  and  young  trees  often  exhibit  minute  galls, 
usually  on  the  upper  surface,  caused  by  mites  of  the  family  Erio- 
phyidae. A  common  form  makes  elongated  pocket  galls  on  the 
pearl  bush,  Exochorda  grandiflora.  Other  forms  are  found  on 
elder,  birch,  maple,  and  elm.  These  mites  do  not  seriously  affect 
the  vitality  of  the  host  but  render  its  appearance  unsightly.  (Shown 
on  Plate  XV,  d). 

Probably  the  best  control  is  a  dormant  spray  of  liquid  lime- 
sulphur  in  early  spring  just  before  the  leaves  appear. 

Aphids  (Family  Aphididae).    See  page  150 

EuoNYMus  Scale  (Chionaspis  cuonymi  Comst.) 

Some  kinds  of  Euonymus,  as  well  as  bitter-sweet,  are  infested 
and  seriously  injured,  even  sometimes  killed,  by  this  scale.  The 
females  are  pear-shaped,  dark  gray,  and  occur  on  leaves  or  tender 
shoots.  The  males  are  smaller,  elongate,  with  parallel  margins, 
and  are  snowy  white.  There  are  said  to  be  two  broods  each  year, 
the  insect  passing  the  winter  as  eggs  under  the  shells  of  the  mother  » 

scale.    This  scale  is  shown  on  Plate  XV,  a.  {' 

The  remedies  are  to  prune  off  and  burn  the  worst-infested  !■ 

stems.    The  remaining  portions  may  then  be  sprayed  in  early  April  !{{ 

with  a  miscible  oil  (i  -  15),  or  in  summer  with  kerosene  emulsion  J- 

containing  15  per  cent  or  more  of  kerosene.  J)| 

(Report  for  1921,  page  185).  ;; 

Rose  Scale  (Aulacaspis  rosae  Bouche)  j\ 

Rose,  blackberry,  and  some  other  plants  are  often  infested  by  ^ 

a  whitish  scale,  nearly  circular,  and  a  little  less  than  one-eighth 
of  an  inch  in  diameter.    These  are  the  female  scales  which,  during  ' 

the  winter,  cover  purple  eggs.    The  male  is  long  and  narrow,  with  ■ 

three  ridges  lengthwise,  and  is  also  white.     This  scale  is  shown  j 

on  Plate  XIV,  a. 

Cutting  and  burning  the  worst-infested  stems  is  recommended; 
then  spray  while  the  plants  are  dormant,  using  either  liquid  lime- 
sulphur  (1-9)  or  a  miscible  oil  (i  -  15). 

(Ohio  Bulletin  332,  page  295).  ! 

White  Peach  Scale  (Aulacaspis  pentagona  Targ.-Tozz.) 

This  has  also  been  called  the  West  Indian  peach  scale,  and 
though  closely  related  to  the  rose  scale,  is  much  less  conspicuous 
on  account  of  the  bark,  dirt,  and  extraneous  matter  on  the  shells. 


l6o  CONNECTICUT  EXPERIMENT  STATION  BULLETIN  292 

In  Connecticut  it  has  been  found  on  cherry,  privet,  and  Catalpa 
Bungei,  but  is  not  beheved  to  be  an  important  or  serious  pest. 
It  is  shown  on  Plate  XIV,  b. 

Spraying  with  a  miscible  oil  or  with  lime-sulphur  when  the  plants 
are  dormant  is  believed  to  be  an  effective  means  of  control. 

(Report  for  1913,  page  240). 

San  Josfe  Scale.    See  page  137 


INSECT  PESTS  OF  EVERGREEN  TREES  AND  SHRUBS 

Key 

A.  Chewing  insects  devouring  leaves  and  buds : 

1.  Larvae  devouring  the  leaves 2 

Larvae  mining  v^rithin  the  leaves 3 

2.  Larvae  an  inch  or  more  in  length,  w^hite,  buff,  or  green,  dotted, 

striped  or  mottled  with  brown  or  black,  feeding  gregariously, 

without  webs,  on  pines Pine  Sawflies,  p.  161 

Larvae  one-half  inch  long,  striped  lengthwise  with  light  and  dark 
brown,  webbing  together  the  twigs  of  juniper, 

Juniper  Webworm,  p.  161 

3.  Minute  larvae  mining  within  the  leaves  of  arborvitae, 

Arborvitae  Leaf-Miner,  p.  161 
Maggots  mining  within  the  leaves  of  box. 

Boxwood  Leaf-Miner,  p.  162 

4.  Destroying  the  terminal  buds  of  pine,  causing  crooked  growth, 

European  Pine  Shoot  Moth,  p.  162 
Destroying  the  terminal  buds  of  spruce Spruce  Budworm,  p.  162 

B.  Attacking  roots  or  stems : 

5.  Gnawing  the  bark  of  the  stems  of  coniferous  seedlings, 

Pales  Weevil,  p.  163 
Gnawing  the  bark  of  the  roots  of  hemlock  and  Taxus, 

Otiorhynchid  Weevils,  p.  163 
Eating  off  the  roots  of  seedlings White  Grubs,  p.  164 

6.  Boring  in  the  leaders  of  white  pine,  causing  them  to  wilt  in  July, 

White  Pine  Weevil,  p.  164 
Boring  in  the  stems  of  rhododendron.  Rhododendron  Borer,  p.  165 

C.  Sucking  juices  from  leaves  or  bark: 

7.  Woolly  aphids :    wax  secretion  prominent   8 

Wax  secretion  slight,  forming  cone-shaped  galls  on  spruce, 

Spruce  Gall  Aphids,  p.  165 

8.  Cotton-like  tufts  of  wax  in  axils  of  leaves  and  white  patches  on 

bark  of  white  pine Pine  Bark  Aphid,  p.  166 

Cottony  wax  secretion  on  leaves  of  larch, 

Larch  Woolly  Aphid,  p.  166 
Cottony  wax  secretion  on  leaves  of  Douglas  fir, 

Douglas-Fir  Woolly  Aphid,  p.  166 

9.  Elongated  white  scales  on  pine  leaves Pine  Leaf  Scale,  p.  166 

Circular  scales  on  leaves  of  juniper Juniper  Scale,  p.  167 

10.    Lace-like   insects   on   under  side  of  leaves   of   rhododendron  and 

Kalviia Rhododendron  Lace  Bug,  p.  167 

Red  spiders  on  leaves Spruce  Mite,  p.  167 


INSECT  PESTS  OF  NURSERY  STOCK  l6l 

Pine  Sawflies  (Family  Tenthredinidae) 
Different  kinds  of  pine  trees  are  sometimes  defoliated  by  sawfly 
larvae  which  usually  feed  gregariously  and  are  whitish,  greenish, 
or  buff,  variously  dotted  or  otherwise  marked  with  black  or  brown. 
They  have  the  habit  of  coiling  the  tail  around  a  leaf  as  a  means  of 
holding  on  to  the  food  plant.  One  of  the  commonest  species  in 
nurseries  is  the  imported  pine  sawfly,  Diprion  simile  Hartig.  The 
larvae  are  slightly  more  than  an  inch  long,  greenish  yellow,  more 
or  less  striped  dorsally  with  brown,  and  the  sides  curiously  spot- 
ted and  reticulated,  as  shown  on  Plate  XIV,  c.  This  species  feeds 
upon  the  white,  Bhotan,  Scotch,  Austrian,  Korean,  Mugho,  and 
several  other  kinds  of  pines,  and  there  are  two  full  generations  each 
season.  Some  of  the  brown  cocoons  are  fastened  to  the  twigs 
and  some  are  placed  upon  the  ground  under  the  trees.  Other  spe- 
cies feeding  on  pine  in  Connecticut  are:  Neodiprion  lecontei 
Fitch,  on  white,  jack,  red,  Scotch,  Austrian,  and  Mugho  pines; 
N.  pinetum  Norton,  on  white  pine,  and  N.  pimis-rigidae  Norton, 
on  pitch  pine. 

The  remedy  is  to  spray  with  lead  arsenate. 
(Report  for  1915,  page  118). 

Juniper  Webworm  (Dichomeris  marginellus  Fabr.) 
Juniper  twigs  are  webbed  together  by  the  larvae  of  this  insect, 
which  feeds  upon  the  leaves  inside  the  nest.  (See  Plate  XIV,  d). 
Low  juniper  in  ornamental  plantings  is  often  defoliated,  but  ap- 
parently Juniperus  hihernica  is  greatly  preferred.  The  caterpil- 
lars are  about  half  an  inch  long,  light  brown,  with  longitudinal 
stripes  of  darker  brown.  The  adult  is  a  moth  with  a  wing-spread 
of  15  mm.,  dark  brown,  with  white  front  and  rear  margins  on  the 
fore-wings.  The  larvae  pupate  in  the  webs,  and  the  moths  appear 
early  in  June,  but  the  life  history  has  not  been  carefully  worked 
out,  and  it  is  possible  that  there  is  more  than  one  generation  each 
year. 

Spraying  heavily  with  lead  arsenate  is  a  satisfactory  remedy. 
(Report  for  191 5,  page  137). 

Arborvitae  Leaf-Miner  {Argyresthia  thuiella  Pack.) 
Small  larvae  mining  in  the  leaves  often  give  a  brown  or  dead 
appearance  to  arborvitae.  (See  Plate  XVI,  b).  The  adult  is  a 
tiny  moth  which  lays  eggs  on  the  leaves  in  June.  There  is  one 
annual  generation,  and  the  insect  spends  the  winter  in  the  cocoon 
in  the  mine. 

Though  remedial  measures  are  of  somewhat  questionable  value, 
it  is  thought  that  a  heavy  application  of  nicotine  solution  and  soap 
or  of  fish-oil  emulsion  may  kill  some  of  the  eggs  or  larvae  and  thus 
prevent  severe  injury  to  the  foliage  by  the  insects. 
(Report  for  1921,  page  157). 


l62  CONNECTICUT  EXPERIMENT  STATION  BULLETIN   292 

Boxwood  Leaf  Miner  (M onarthropalpus  buxi  Labou) 

The  adult  of  this  insect  is  a  yellow  midge  or  two-winged  fly 
which  lays  eggs  in  the  leaves  in  May,  and  the  maggots  feed  and 
develop  between  the  upper  and  lower  epidermal  layers,  causing 
a  blistering  and  distortion  of  the  leaves,  often  called  galls.  (Shown 
on  Plate  XVI,  a).  The  foliage  is  usually  thin  on  infested  plants. 
The  maggots  live  over  winter  in  the  leaves  and  pupate  in  spring. 

The  remedy  is  to  spray  the  plants  with  a  cheap  molasses,  one 
part  in  four  parts  of  water,  with  the  addition  of  nicotine  sulphate, 
one  part  in  500  parts  of  the  spray  material.  The  first  application 
should  be  made  when  the  adults  first  begin  to  emerge  from  the 
infested  leaves,  and  the  plants  should  be  kept  covered  for  three 
weeks.  One  application  each  week  will  answer  in  fair  weather, 
but  the  plants  should  be  sprayed  after  each  rain. 

(Report  for  1923,  page  312;  Maryland  Bulletin  272). 

European  Pine  Shoot  Moth  (Rhyacionia  (Evetria)  hiioliana 

Schiff.) 

This  is  a  serious  pest  of  all  kinds  of  pines  in  Europe  and  is 
now  present  in  Fairfield  County,  Connecticut,  where  it  seems  to 
prefer  the  red  pine.  The  adult  is  a  small  orange  moth  which  in 
August  lays  eggs  singly  on  the  newly  formed  terminal  buds  which 
are  ready  for  next  year's  growth.  The  young  larvae  soon  eat  their 
way  into  the  buds  and  excavate  cells  in  which  they  spend  the  win- 
ter. The  following  spring  the  larva  leaves  its  winter  home  and 
bores  into  the  next  bud,  and  thus  destroys  as  many  buds  as  may  be 
needed  for  food.  It  also  attacks  the  young  shoots,  feeding  on  one 
side,  causing  them  to  become  curved  and  deformed.  When  ma- 
ture, the  larva  pupates  in  an  excavated  shoot,  and  three  weeks 
later  the  moth  emerges.  Apparently  there  is  only  one  generation 
each  year.  Distorted  and  crooked  growth  called  "bayonet  shoots" 
follows  the  attack  of  this  insect. 

No  remedy  is  known  other  than  to  prune  and  burn  the  infested 
buds  and  shoots. 

(U.  S.  D.  A.  Bulletin  170). 

Spruce  Budworim   {Harmologa  fumiferana  Clem.) 

Spruce  and  balsam  trees  are  often  severely  injured  by  this  in- 
sect. The  moths  emerge  in  June  and  July  and  the  females  lay 
upon  the  needles  their  eggs,  which  hatch  in  ten  days,  but  the  larvae 
do  little  or  no  feeding  until  the  following  spring.  They  pass  the 
winter  in  protective  cases  which  they  spin  in  crevices  on  the  tree 
or 'Other  convenient  shelters.  The  young  caterpillars  feed  for 
about  three  weeks  in  the  spring  at  the  base  of  needles  upon  the 
terminal  shoots,  moving  about  freely.     The  severed  needles  are 


INSECT  PESTS  OF  NURSERY  STOCK  163 

loosely  attached  to  the  twigs  by  the  silk  threads  spun  by  the  larvae. 
When  fully  grown  each  larva  is  about  three-fourths  of  an  inch 
long,  and  it  then  pupates  upon  the  tree.  The  adult  moth  is  gray 
with  brown  markings  and  white  spots.  There  is  only  one  annual 
generation. 

Spraying  heavily  with  lead  arsenate  will  doubtless  prove  effec- 
tive in  the  nursery  and  on  small  ornamental  trees. 

(Manual  of  Tree  and  Shrub  Insects,  page  285). 


Pales  Weevil  (Hylobiits  pales  Herbst) 

This  insect  is  a  Curculionid  or  snout  beetle  less  than  half  an 
inch  in  length.  In  color  it  varies  from  dark  reddish-brown  to 
black,  and  usually  has  gray  or  whitish  hairs  so  arranged  as  to 
form  small  spots  on  the  wing-covers.  This  beetle  is  believed  to  be 
responsible  for  the  failure  of  much  of  the  forest  planting  where 
conifers  are  used  and  has  also  injured  seedlings  in  nurseries  by 
eating  off  the  bark  of  the  stems,  thus  in  effect  girdling  the  young 
trees.  Nearly  all  kinds  of  coniferous  trees  are  attacked,  and  the 
feeding  is  done  at  night.  There  is  only  one  generation  each  year, 
and  the  beetles  hibernate  in  the  soil  at  the  base  of  the  trees.  The 
eggs  are  laid  and  the  larvae  feed  in  pine  stumps  and  logs. 

As  a  control  measure,  seedlings  or  nursery  stock  should  not  be 
grown  in  close  proximity  to  pine  logs,  stumps,  or  lumber. 

(Harvard  Forest  Bulletin  3). 

Otiorhynchid  Weevils   {Otiorhynchus  sulcatus  Fabr.  and 
0.  ovatus  Linn.) 

Ta.vus  plants  are  occasionally  injured  in  nurseries  by  the  grubs 
or  larvae  of  Otiorhynchus  sulcatus  Fabr.,  a  black  snout  beetle  with 
faint  gray  spots,  half  an  inch  in  length,  commonly  called  the 
black  vine  weevil,  and  shown  on  Plate  XVIII,  b. 

A  case  of  injury  occurred  in  a  nursery  in  1913:  The  smaller 
roots  had  been  devoured,  and  the  larger  ones  and  the  main  stem 
had  been  girdled.  In  1909,  hemlock  trees  from  12  to  18  inches 
tall  showed  signs  of  unthriftmess,  failed  to  grow,  and  some  of 
them  dropped  their  leaves.  At  the  roots  were  grubs,  pupae,  and 
adults  of  Otiorhynchus  ovatus,  commonly  known  as  the  strawberry 
crown  girdler.  This  species  is  about  one-fourth  of  an  inch  long 
and  is  brown  without  color  markings.  This  smaller  species  had 
girdled  the  main  stem  and  larger  roots. 

Treating  the  soil  with  an  emulsion  of  carbon  disulphide,  as  is 
done  to  kill  the  grubs  of  the  Japanese  beetle  and  the  Asiatic  beetle, 
may  be  recommended  in  severe  infestations. 

(Report  for  1909,  page  370;  191 3.  page  230). 


1 64 


CONNECTICUT  EXPERIMENT  STATION 


BULLETIN  292 


White  Grubs  {Phyllophaga  or  Lachnosterna  sps.) 

The  larvae  of  May  or  June  beetles  occasionally  eat  off  the  roots 
of  coniferous  trees  in  nurseries.  There  are  probably  several  spe- 
cies involved,  and  most  of  them  require  three  years  to  complete 
the  life  cycle.  The  injury  is  usually  the  most  severe  the  third  sea- 
son, when  the  grubs  are  large  and  voracious.  Shown  in  Figs. 
30  and  31. 

In  some  cases  it  may  be  possible  to  treat  the  soil  about  the  plants 
with  an  emulsion  of  carbon  disulphide. 

(Report  for  1912,  page  288). 


Fig.  30.    White  grub  and  its  adult, 
the  common  June  beetle. 


Fig.  31.    Pine  seedling  with  roots  eaten  off  by  white  grubs. 


White  Pine  Weevil  (Pissodes  strobi  Peck) 

The  white  pine  weevil  probably  causes  more  injury  to  white 
pine  trees  in  Connecticut  than  any  other  insect,  and  perhaps  more 
than  all  other  insects  together.  It  also  injures  spruce  trees.  There 
is  one  annual  generation,  and  the  beetles  hibernate  somewhere  dur- 
ing the  winter  and  appear  on  the  pine  trees  about  May  i.  They 
make  punctures  in  the  bark  of  the  leaders  or  terminal,  shoots  of 
the  preceding  season's  growth.  In  some  of  these  punctures  eggs 
are  laid  and  soon  hatch.  The  grubs  feed  in  the  cambium  and 
sometimes  in  the  pith,  becoming  mature  in  about  six  weeks,  when 
they  excavate  cells  in  the  wood  in  which  they  pupate.  Late  in 
July  and  continuing  until  September,  the  adult  beetles  emerge. 
The  infested  leaders  wilt  in  July  and  later  turn  brown  and  die. 
In  time  a  lateral  branch  will  grow  upright  and  take  the  place  of 


INSECT  PESTS  OF  NURSERY  STOCK  165 

the  leader,  but  this  makes  crooked  and  ill-shaped  trees.  The 
injury  caused  by  this  insect  is  shown  in  Fig.  32  and  on  Plate 
XVIII,  c. 

Trees  may  be  partially  protected  by  spraying  the  leaders  about 
May  I  with  either  lead  arsenate  or  liquid  lime-sulphur  (i  -9). 

(Report  for  1919,  page  144). 


Fig.  32.    Pupal  cases,  larval  cells,  and  exit  holes  of  the  white  pine  weevil. 
About  twice  natural  size. 

Rhododendron  Borer  (Sesia  rhododendri  Beut.) 

Serious  injury  to  rhododendrons  in  ornamental  plantings  has 
been  caused  by  the  rhododendron  borer  in  Connecticut,  though  the 
work  of  the  insect  has  not  been  very  noticeable  in  nurseries.  The 
adult  is  a  wasp-like  clear-wing  moth  v/hich  lays  eggs  in  late  May 
or  June  on  the  twigs.     The  larva  soon  after  hatching  tunnels  into 

the  sapwood  of  the  stem,  where  it  forms  irregular  galleries  from  j! 

one  to  two  inches  long,  usually  just  below  a  crotch.     Larvae  are  j- 

yellowish- white,  about  half  an  inch  long,  and  usually  become  full  ]■, 

grown  by  October  but  remain  in  their  galleries  through  the  winter  •'' 

and  pupate  there  in  the  spring.     Two  weeks  later  the  moths  ap-  > 

pear,  and  there  is  only  one  annual  generation.  !: 

The  injured  stems  cannot  supply  the  necessary  moisture  and  the  jil 

leaves  turn  brown  and  die.     The  stems  are  often  broken  at  the  jil 

point  of  injury.     Rhododendron  maximum  is  perhaps  more  se-  ;J| 

verely  injured  than  other  species,  but  hybrid  rhododendrons  are  !j 

also  attacked.    The  injury  is  shown  on  Plate  XVII,  a.  i 

There  is  no  remedy  except  to  cut  out  the  borers  and  to  prune  i 

off  and  burn  infested  stems  and  branches.  ; 

(Report  for  1922,  page  347).  i 

i 

Spruce  Gall  Aphids   {Adelges,  Chermes,  sps.) 

One  of  the  commonest  pests  in  nurseries  is  the  spruce  gall  aphid, 
Adelges  abietis  Linn.,  which  forms  cone-shaped  galls  at  the  base 
of  the  new  growth  on  Norway  spruce,  and  sometimes  black,  red, 
and  white  spruce  trees  are  infested  to  a  less  extent.  There  are 
two  broods  each  season,  the  winter  being  passed  by  the  immature 
females  on  the  twigs.  They  reach  maturity  and  lay  on  the  leaves 
masses  of  eggs  which  hatch  soon  after  the  new  shoots  appear  in 
May.     The  young  aphids  crawl  to  the  base  of  the  shoots  and  at- 


l66  CONNliCTICUT  EXPliRIMENT  STATION  BULLETIN   292 

tach  themselves  where  the  irritation  resulting  from  their  feeding 
causes  the  needles  to  swell  at  the  base  until  they  touch  each  other. 
Thus  pockets  are  formed  in  which  the  young  aphids  are  enclosed, 
and  the  result  is  one  continuous  gall,  shaped  like  the  cone  of  the 
tree.  These  galls  break  open  in  August,  and  the  aphids  go  to  the 
leaves  and  soon  transform  to  mature  females  which  lay  eggs  for 
the  second  brood.    One  of  the  galls  is  shown  on  Plate  XVII,  c. 

Larger  terminal  galls  on  the  Colorado  blue  spruce  are  formed  by 
Gillettea  cooleyi  Gill.,  (see  Plate  XVII,  b),  and  a  form  known  as 
variety  cozveni  Gill,  is  the  woolly  aphid  common  upon  the  leaves 
of  Douglas  fir.  Another  species,  Adelges  (Chermes)  strobilobius, 
is  known  as  the  larch  woolly  aphid,  and  is  common  on  larch  foli- 
age in  midsummer. 

The  remedy  is  to  spray  the  trees  early  in  April  with  a  miscible 
oil  (i  -  25),  to  kill  the  overwintering  females.  The  summer  forms 
on  leaves  may  be  killed  by  spraying  with  nicotine  solution  and 
soap. 

(Report  for  1926,  page  223). 


Pine  Bark  Aphid  [Adelges  (Chermes)  pinicorticis  Fitch] 

Small,  cotton-like  tufts  of  wax  in  the  axils  of  the  leaf  clusters 
are  common  on  small  white  pine  trees,  and  on  larger  ones  large 
white  patches  on  the  bark  are  often  seen.  The  pine  bark  aphid  is  the 
cause,  but  its  life  history  is  not  fully  known.  Eggs  hatch  about 
May  I,  and  the  young  settle  along  the  twigs  and  suck  the  sap  from 
the  bark,  soon  becoming  covered  with  slender  filaments  of  wax, 
giving  them  the  appearance  of  small  tufts  of  cotton,  as  shown  on 
Plate  XVIII,  a. 

Trees  can  be  entirely  cleared  of  this  insect  by  a  thorough  spray- 
ing in  June  with  kerosene  emulsion,  and  probably  nicotine  solu- 
tion and  soap  will  prove  equally  effective. 

(Report  for  1919,  page  155). 


Pine  Leaf  Scale  (Chionaspis  pinifoliae  Fitch) 

Often  small  pine  trees  show  elongated  white  scales  on  the  leaves. 
This  is  the  pine  leaf  scale  which  infests  Mugho,  Austrian,  jack, 
red,  Scotch,  stone,  and  white  pines,  sometimes  killing  them.  There 
are  two  generations  each  year,  and  purple  eggs  under  the  female 
shells  carry  the  species  through  the  winter.  These  eggs  begin  to 
hatch  in  May,  but  the  hatching  period  is  a  long  one,  and  the  two 
broods  are  not  distinct  but  overlap. 

Illustrations  of  this  scale  are  shown  on  Plate  XV,  c. 

Control  measures  for  this  insect  have  not  been  given  a  thorough 
trial  in  Connecticut,  but  it  can  doubtless  be  held  in  check  bv  dor- 


INSECT  PESTS  OF  NURSERY  STOCK  167. 

mant  spray  applications  of  liquid  lime-sulphur  (i  -9),  or  of  mis- 
cible  oil   (i  -  15)  in  April,  and  of  nicotine  solution  and  soap  be- 
tween June  I  and  August  i. 
(Report  for  1921,  page  181). 


Juniper  Scale   {Diaspis  carueli  Targ.-Tozz.) 

Small,  circular,  whitish  scales  1-2  mm.  in  diameter  are  often 
present  and  sometimes  very  abundant  on  the  leaves  of  juniper, 
resulting  in  a  yellow  and  sickly  appearance. 

Spraying  with  a  miscible  oil  (1-25)  in  spring,  before  the  new 
growth  starts,  will  probably  control  this  insect. 

(Report  for  1920,  page  212). 


Rhododendron  Lace  Bug  (Leptobyrsa  rlwdodendri  Horvath) 

This  is  a  sucking  bug  belonging  to  the  family  Tingidae  and  com- 
monly called  lace  bug.  It  is  on  the  under  side  of  the  leaves  of  rho- 
dodendron, especially  R.  maxima,  and  Kalmia  latifoUa  or  moun- 
tain laurel.  Apparently  there  is  only  one  brood  each  year.  The 
eggs  are  laid  along  the  midrib,  and  there  is  much  brownish  dis- 
coloration from  the  excrement.  The  injured  leaves  show  whitish 
spots  on  the  upper  surface.  (See  Plate  XX,  d). 

Spraying  the  under  sides  of  the  leaves  with  nicotine  solution 
and  soap  when  the  bugs  are  present  has  been  efitective. 

(Report  for  1921,  page  200). 


Spruce  Mite  (ParatetranycJius  ununguis  Jacobi) 

Spruce  trees  and  other  evergreens  are  often  severely  injured  by 
Inites.  Such  injury  is  noticed  somewhere  in  the  State  each  year, 
though  it  is  usually  more  severe  and  more  widespread  in  seasons 
of  drought.  The  leaves  are  peppered  with  small  whitish  spots, 
covered  with  brownish  eggs  and  egg-shells,  and  are  usually  more 
or  less  webbed  together.  The  greenish-yellow  living  mites  and 
their  cast  skins  are  also  abundant. 

Spraying  in  spring  before  the  new  growth  starts  with  a  mis- 
cible oil  (1-15)  to  kill  the  eggs,  and  the  application  of  liquid 
lime-sulphur  (1-50)  or  linseed  oil  emulsion  to  kill  the  mites  in 
midsummer,  are  recommended.  Some  of  the  oil  preparations  are 
apt  to  remove  the  bloom  from  some  of  the  varieties  of  blue  spruce. 

(Report  for  1922,  page  340). 


l68  CONNECTICUT  EXPERIMENT  STATION  BULLETIN   292 


INSECTS  INJURING  PERENNIAL  PLANTS 
Key 
Chewing  Insects : 

1.  Attacking  the  leaves 2 

Attacking  the  stem  or  root 5 

2.  Devouring  the  leaves 3 

Mining  vi^ithin  the  leaves  of  columbine, 

Columbine  Leaf-Miner,  p.  168 

3.  Perforating  or  devouring  portions  of  the  entire  thickness  of  the 

leaves    4 

Minute  jumping  insects  feeding  on  surface  of  leaves  of  seedlings, 

Garden  Spring-Tail,  p.  169 

4.  Feeding  at  night,  hiding  during  the  day: 

Larvae  with  true  legs,  curled  up  in  soil  around  base  of  plant. 

Climbing  Cutworms,  p.  130 
Gray  or  brown  slugs  without  legs,  hiding  under  rubbish  and  leav- 
ing a  slimy  trail Garden  Slugs,  p.  170 

5.  Cutting  off  the  stem  near  the  surface  of  the  ground: 

Larvae  curled  up  in  soil  near  the  plant Cutworms,  p.  169 

Striped  larva  boring  lengthwise  in  stem Stalk  Borer,  p.  170 

Pink  larva  burrowing  in  rootstocks  of  iris.. Iris  Root  Borer,  p.  171 

Sucking  Insects : 

6.  Visible  insects  attacking  leaves  or  shoots  at  tip 7 

Reddish  mites  with  eggs  and  shells  injuring  leaf  surface, 

Red  Spider,  p.  150 

Microscopic,   glassy  mites,   curling  leaves   of   larkspur   and    some 

other  plants Cyclamen  Mite,  p.  172 

7.  Exceedingly  active  flying  bugs,  with  nymphs  on  leaves 8 

Rather  inactive  plant-lice  on  leaves  or  stems     Aphids,  p.  150 

8.  Greenish-yellow  bugs ;  adult  with    four   black  stripes,  on  terminal 

leaves  Four-lined  Plant  Bug,  p.  172 

Grayish  or  brownish  bugs  on  terminal  leaves, 

Tarnished  Plant  Bug,  p.  139 


Columbine  Leaf-Miner  {Phytomyza  aquilegiae  Hardy) 

In  June,  whitish  serpentine  mines  begin  to  appear  in  the  lower 
leaves  of  columbine.  There  are  often  several  miners  in  a  leaf, 
and  the  mines  may  continue  to  increase  in  size  until  the  entire 
leaf  is  involved.  Later  the  small  leaves  around  the  flower  stalks 
are  infested.  There  are  several  generations,  the  winter  being 
passed  as  pupae  in  the  ground.  The  eggs  are  laid  in  the  under 
sides  of  the  leaves  and  hatch  in  less  than  a  week.  The  larvae 
mine  between  the  upper  and  lower  epidermal  layers  of  the  leaf, 
becoming  mature  in  about  two  weeks,  and  emerge  from  the  mines 
through  crescent-shaped  openings.  They  attach  themselves  to  the 
leaf  and  pupate.  In  two  weeks  the  adults  emerge.  They  are 
small,  dark  brown  flies  about  2  mm,  long.  Injured  leaves  are 
shown  on  Plate  XX,  a. 


INSECT  PESTS  OF  NURSERY  STOCK  169 

Cultivating  the  ground  around  the  plants  in  late  fall  or  early 
spring  will  reduce  the  infestation.  Removing  and  destroying  the 
mined  leaves  when  the  infestation  first  appears  will  aid  in  the  con- 
trol of  this  pest. 

(Report  for  1894,  page  145 ;  New  Jersey  Department  of  Agri- 
culture, Circular  36,  page  13). 


Garden  Spring-Tail  (Sminthurus  hortensis  Fitch) 

Small  seedling  plants,  particularly  in  hotbeds  or  cold  frames,  are 
often  injured  in  early  spring  by  minute,  purplish,  jumping  insects 
which  eat  off  the  surface  tissue  from  the  leaves.  These  tiny  in- 
sects are  purple,  spotted  with  yellow,  and  jump  like  fleas.  Each 
has  a  globular-shaped  body  and  rather  large  head  with  narrow 
neck.  A  forked  tail-like  appendage  used  in  jumping  extends  rear- 
ward from  the  under  side  of  the  body,  as  shown  in  Fig.  33. 


Fig.  S3-    Garden  spring-tail.  Fig.  34.     Cutworm  and  characteristic 

injury  to  plant. 

This  insect  may  be  controlled  by  spraying  or  dusting  the  plants 
with  nicotine. 

(Bulletin  6,  Tobacco  Experiment  Station,  page  86  T). 


Cutworms  (Noctuidae,  several  species) 

Perennial  plants,  especially  the  seedlings  and  tender  shoots,  are 
often  cut  off  near  the  ground  by  cutworms,  as  shown  in  Fig.  34. 
There  are  also  other  kinds  of  cutworms  which  climb  and  feed  upon 
the  leaves.  Most  of  the  cutworms  are  single-brooded  and  live 
through  the  winter  as  partially  grown  larvae.  The  adult  moths 
emerge  and  lay  their  eggs  in  late  summer.  All  cutworms  are  the 
larvae  of  rather  inconspicuous  gray  or  brown  moths  of  the  family 
Noctuidae,  and  there  are  perhaps  a  dozen  or  more  species  that  are 
classed  as  cutworms. 

Injury  from  the  climbing  cutworms  may  be  lessened  by  spraying 
the  foliage  with  lead  arsenate.     The  cutworms,  which  cut  off  the 


170  CONNECTICUT  EXPERIMENT  STATION  BULLETIN   292 

stems  of  plants,  can  best  be  controlled  with  a  poisoned  bait  distrib- 
uted about  the  field  a  few  days  before  the  injury  becomes  serious. 
A  formula  for  this  bait  is  as  follows : 

Wheat  bran 5  lbs. 

White  arsenic  or  Paris  Green  4  oz. 

Cheap   molasses    i  pint 

Orange  or  lemon   i   fruit 

Water 7  pints 

Cut  the  fruit  into  small  pieces  and  mix  together  to  form  a  rather  dry 
mash  and  scatter  around  the  field. 


Garden  Slugs  (Family  Limacidae) 

The  leaves  of  garden  plants  are  often  eaten  by  slugs,  which  are 
closely  related  to  snails  but  without  the  usual  shell.  One  of  the 
commonest  species  is  the  gray  field  slug,  Agriolimax  agrcstis  Linn., 
and  another  and  more  striking  species  is  the  giant  or  spotted  gar- 
den slug,  Umax  maximus  Linn.,  shown  in  Fig.  35. 


Fig.  35.     Spotted  garden  slug,  natural  size.     (After  Kingsley, 
Riverside  Natural  History). 

These  animals  feed  at  night  on  the  tender  leaves  of  garden  and 
greenhouse  plants,  eating  holes  through  the  leaves  or  notches  in 
the  margins.  They  hide  under  rubbish  during  the  day  and  leave  a 
slimy  trail  wherever  they  crawl. 

Plants  may  be  protected  by  spraying  or  dusting  with  lead  arse- 
nate. As  a  rule,  beds  may  be  protected  by  surrounding  them  with  a 
layer  of  air-slaked  lime,  but  fine  soot  or  coal  ashes  will  answer 
the  purpose,  as  the  slugs  do  not  like  to  crawl  through  such  dry 
material. 

(Report  for  1918,  page  333). 

Stalk  Borer  {Papaipema  nchris  Guen.) 

The  stalk  borer  may  be  found  in  any  kind  of  herbaceous  stem 
and  attacks  vegetables,  annual  and  perennial  flowering  plants, 
and  weeds.  (See  Fig.  36).  Among  the  perennials  it  is  often  found 
in  hollyhock,  lily,  larkspur,  peony,  and  chrysanthemum.  There  is 
a  single  generation  each  year,  and  the  insect  passes  the  winter  as 
an  egg  on  the  stem  of  dead  grass.    The  eggs  hatch  in  May  and  the 


INSECT  PESTS  OF  NURSERY  STOCK 


171 


larvae  begin  to  tunnel  in  grass  stems,  later  migrating  to  other 
plants.  By  August  or  early  September,  the  larvae  mature  and 
pupate  in  the  burrows ;  a  month  later  the  adults  emerge.  The 
moth  has  a  vi^ing-spread  of  about  one  and  three-eighths  inches 
and  is  brown,  with  conspicuous  white  discal  spots  on  the  fore 
wings.    Larva  and  adult  are  shown  on  Plate  XX,  b  and  c. 

Heretofore  the  only  remedy  has  been  to  cut  out  the  borer,  burn 
the  infested  stalks,  or  inject  carbon  disulphide  into  the  burrow  and 
plug  the  opening.     Burning  the  grass  and  weeds  around  the  fields 


Rl 


Fig.  36.    Stalk  borer. 

in  late  fall  or  early  spring  is  now  known  to  have  a  tendency  to  re- 
duce the  number  of  stalk  borers  by  killing  the  eggs. 

(Report  for  19 19,  page  180.     New  Hampshire  Technical  Bul- 
letin 34). 


Iris  Root  Borer  (Macrouoctua  onusta  Grote) 

The  rootstocks  of  iris  plants  are  injured  by  a  pink  larva  tunnel- 
ing in  them,  often  devouring  the  entire  rootstock  and  killing  the 
plant.  This  is  the  larva  of  a  brown  moth  with  a  wing-spread  of 
about  two  inches,  which  probably  has  only  one  generation  each 
year.  The  adults  emerge  in  September  or  October  and  la}'  eggs 
upon  the  iris  leaves.  These  eggs  hatch  in  spring,  and  the  young 
borers  find  their  way  into  the  rootstock,  where  they  feed  and  in- 
crease in  size,  becoming  fully  grown  in  August.  They  then  pupate 
in  the  ground,  and  later  the  adults  emerge.  Larva  and  moth  are 
shown  on  Plate  XIX,  b  and  c. 

Gathering  and  burning  the  leaves  in  late  fall  or  early  spring  to 
destroy  the  eggs  is  the  only  remedy  known. 

(Report  for  1918,  page  331). 


1/2 


CONNECTICUT  EXPERIMENT  STATION 


BULLETIN  292 


Red  Spider  (Tetranychus  bimaculatus  Harv.)     See  page  150 

Cyclamen  Mite  {Tarsonemus  pallidus  Banks) 

This  mite  often  injures  larkspur  and  several  annual  plants  in 
the  garden,  as  well  as  cyclamen,  snapdragon,  and  chrysanthemum 
in  the  greenhouse.  The  new  leaves  become  thickened  and  more 
or  less  curled,  as  shown  on  Plate  XIX,  a.  Buds  are  also  distorted 
and  fail  to  open  properly.  The  mites  are  almost  too  small  to  be 
seen  by  the  naked  eye,  but  under  the  magnifying  glass  they  are 
white  and  glassy. 

Frequent  and  thorough  spraying  with  nicotine  solution  and  soap, 
one  part  in  500  parts  of  water,  if  started  when  the  injury  first 
appears,  will  control  this  pest.  This  treatment  should  be  repeated 
each  week  and,  in  severe  cases,  twice  each  week. 

(Report  for  1914,  page  176). 

Aphids  (Family  Aphididae).     See  page  150 


Fig.  2i7-    Four-lined  plant  bug  and  injured  currant  leaf. 


Four-Lined  Plant  Bug  (Poecilocapsus  lineatus  Fabr.) 

This  greenish-yellow  bug  is  about  three-eighths  of  an  inch  long 
in  the  adult  stage  and  has  four  black  stripes  on  its  back.  In  early 
spring  when  first  hatched,  it  is  bright  red,  with  large  black  spots  on 
the  thorax.  The  eggs  are  laid  by  the  adult  bugs  late  in  June  or 
early  July,  but  do  not  hatch  until  the  following  spring.  The 
young  nymphs  feed  for  about  three  weeks  and  reach  the  adult 
or  winged  stage  about  the  middle  of  June.  There  is  but  one  gen- 
eration each  year.  This  insect  has  a  wide  range  of  food  plants, 
being  particularly  injurious  to  dahlia,  rose,  currant,  gooseberry, 
and  mint. 


INSECT  PESTS  OF  NURSERY  STOCK  1 73 

It  gets  its  nourisliment  by  sucking  the  juices  from  the  tenderest 
leaves  near  the  ends  of  the  shoots.  The  injured  leaves  turn  brown 
in  spots,  which  later  become  transparent,  and  in  heavy  infesta- 
tions the  entire  leaf  turns  brown.     (See  Fig.  37). 

The  adults  are  shy  and  very  active  when  alarmed  and  very  dif- 
ficult to  capture.  As  they  fly  readily,  they  are  not  easily  killed  by 
sprays.  The  nymph,  having  no  wings,  may  be  killed  by  a  spray 
of  nicotine  and  soap,  and  some  of  the  adults  will  hkewise  be  hit 
and  killed. 

(Report  for  1914,  page  189). 

Tarnished  Plant  Bug  {Lygus  prate)isis  Linn.)     See  page  139 


PLATE  I. 


'■^^■■j^^r^W^^f.. 


a.   Adult  female  and  egg-mass  of  fall 
cankerworm.    Twice  natural  size. 


b.     Egg-mass  of  fall  cankerworm  on 
t\,vig.   Four  times  enlarged. 


__sd_ 


c.     Apple  leaf  parth'  devoured  by 
cankerworms. 


d.     Leopard   moth  larva   in   its 
burrow.     Natural  size. 


PLATE  II. 


Nests   of   fall   web-worni. 
(After  Slingerland). 


c.     White-marked  tussock  moth 
caterpillar.    Natural  size. 


b.  Hickory  tussock  moth.  Fully 
grown  caterpillar  on  leaf. 
Natural  .^ize. 


d.       Gipsy  moth  caterpillar.    Natural 
size. 


e.     Gipsy  moth  egg-mass  and  pupa. 
Natural   size. 


f.  White-marked  tussock  moth.  Nat- 
ural size.  Female  moth  and 
egg-masses. 


PLATE  III. 


igi5jS4?i&*«'^-G. 


a.     Oyster-shell   scale  on  poplar. 
Natural    size. 


I).     European  fruit  lecanium  on 
blackberry.    Natural   size. 


c.     Nest  of  tent  caterpillar. 


d.     Egg-mass   of   fent   caterpillar 
on  twig.    Natural  size. 


e.     Tent  caterpillars,  partially  grown.    Natural  size. 


PLATE  IV. 


a.     Apple  and  thorn  skeletonizer ;  apple  leaf  eaten  by  caterpillar,  and  cocoon. 

Somewhat  reduced. 


b.    Japanese  beetle;  adults  twice  enlarged. 


c.     Rose  leaves  eaten  by  Japanese  beetles.    Natural  size. 


PLATE  V. 


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a.     Bircli   leaf  injund  by  the  rose  chafer.     Xatural  size. 


b.     Peach  twigs  injured  by  larvae  of  the  Oriental  peach  moth.    Xatural  size. 


PLATE  VI. 


b.      Yellow-necked   caterpillars. 
Natural  size. 


a.    Red-humped  caterpillar.   Enlarged 
one  and  one-half  times. 


c.  Budded  fruit  trees,  showing  where 
buds  were  destroyed  by  climb- 
ing cutworms.    Natural  size. 


d.    Peach  borer  in  base  of  young 
tree. 


PLATE  Vll. 


a.    San  Jose  scale  on  peach  twig. 
Twice   natural   size. 


b.     Green  aph:d=  mm  apple  leaf. 
Natural  size. 


c.  Wooll:/  ari-.ids  u;;  f.vig;,  showing 
galls  and  white  flocculent  ap- 
pearance. 


d.      Eggs   of   European   red 
mite.   Ten  times  enlarged. 


Scurfy  scale  on  currant; 
males  at  left:  females 
at  right. 


e.     Leaf   showing  v^-ork   of 

pear  leaf  blister  mite. 

Xatural  size. 


PLATE  VIII. 


a.     Leaves  of  gray  birch  injured  by  the  imported  birch  leaf  miner. 


b.     Larvae  of  birch  skeletonizer  on  leaf  of  gray  birch.    Slightly  enlarged. 


PLATE  IX. 


<^      31^ 


a.    Larvae  and  pupae  of  the  larch  sawfly.    Natural  size. 


b.     Elm  leaf  licetle  larvae  and  their  work.     Natural  size. 


c.    Larvae,  pupa  and  adult  of  imported  willow  leaf  beetle  and  injur}-  to 
willow  leaves.     Slightly  enlarged. 


PLATE  X. 


a.     Work  of  poplar  and  willow  borer.     Natural   size. 


b.     Linden  borer,  natural  size,  and  its  injury  to  }^oung  linden  trees, 
erreatlv  reduced. 


PLATE  XL 


a.    European  elm  scale.     Natural  size. 


b.     Terrapin    scale.     Xatural   size. 


c.     Pit-making  oak  scale.     Natural  size. 


d.     Tulip  tree  scale. 
Natural  size. 


e.    Cotton}'  maple  scale.     Natural  size. 


PLATE  XI!. 


b.    Eight-spotted  forester.     Adults  and  larvae, 
natural    size. 


a.     Saddle-back  caterpillar. 
Twice  enlarged. 


c.     lo  caterpillars.     Natural  size. 


d.      Pipe-vine   caterpillar. 

Natural  size. 


e.    Cecropia  caterpillar.     Natural  size. 


PLATE  XIII. 


a.     Lilac  borer,  showing  adult  pupa  case  and  injured  privet  stem. 
Natural  size. 


b.     Galls  of  rose  stem  girdler,  twice  enlarged. 


PLATE  XIV. 


a.     Rose  scale,  twice  enlarged.  b.    White  puach  scaiL,  uvice  enlarged. 


Imported  pine  sawfly  larvae  feed- 
ing on  leaves.     Natural  size. 


d.    Work  of  juniper  webworm. 


PLATE  XV. 


a.  Euonymus  scale,  mostly  males.  A 
tew  larger,  gray  females  are 
present. 


b.     Grape-vino  tomato  gall. 


c.     Pine  leaf  scale,  twice  enlarged. 


e.     Oak   gall   scale. 


d.     Mite  galls  on  leaves  of  Exochorda. 


PLATE  XVI 


a.     Boxwood  leaf  miner.     White  spots  on  leaves  indicate  infestation.     Lower 
epidermis  has  been  removed  from  two  leaves,  showing  maggots.     Natural  size. 


b.     Work  of  arbor vitae  leaf  miner,  twice  enlarged. 


PLATE  XVU. 


a.     Rhododendron  borer.     Appearance  of  mfested   stems   showing  adult. 

Natural  size. 


b.    Gall  of  blue  spruce.   Natural  size.  c.    Spruce  gall.   Natural  size. 


PLATE  XVIII. 


a.     Pine  bark  aphid  in  small  tufts  on  twigs  and  leaves.    Natural  size. 


b.     Otiorhynchus  sulcatus  Fabr.     Larva,  pupa,   and  adult. 
Twice  enlarged. 


c.     Exit  holes  of  white  pine  weevil.     Natural  size. 


PLATE  XIX. 


a.     Larkspur  leaves  curled  by  cyclamen  mites;  healthy  leaf  at  left. 
Somewhat  reduced. 


c.     Iris  root  borer, 
b.    Adult  of  iris  root  borer.   Natural  size.  Natural  size. 


PLATE  XX. 


Adult  of   stalk  borer. 
Natural  size. 


Work  of  columbine  leaf  miner. 
Natural  size. 


c.     Immature  stalk  borer  in  corn. 
Natural  size. 


Rhododendron  leaves  injured  by  rhododendron  lace  bug,  which  may  be 
seen  on  lower  surface  at  right.  Leaf  at  left  shows  appearance  on 
upper  surface. 


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